* [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel @ 2018-07-01 22:04 tomas 2018-07-02 1:10 ` Ian Kent 0 siblings, 1 reply; 10+ messages in thread From: tomas @ 2018-07-01 22:04 UTC (permalink / raw) To: raven, autofs; +Cc: linux-kernel, syzkaller Hi, I've looked into this issue found by Syzbot and I made a patch: https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425b1163 The autofs subsystem does not check that the "path" parameter is present within the "param" struct passed by the userspace in case the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a path is always provided (though a path is not always present, as per how the struct is defined: https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_dev-ioctl.h#L89). Skipping the check provokes an oob read in "strlen", called by "getname_kernel", in turn called by the autofs to assess the length of the non-existing path. To solve it, modify the "validate_dev_ioctl" function to check also that a path has been provided if the command is AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200 +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s goto out; } } + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) + return -EINVAL; err = 0; out: Tested and solves the issue on Linus' main git tree. Tomas ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-01 22:04 [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel tomas @ 2018-07-02 1:10 ` Ian Kent 2018-07-02 1:42 ` Ian Kent 0 siblings, 1 reply; 10+ messages in thread From: Ian Kent @ 2018-07-02 1:10 UTC (permalink / raw) To: tomas, autofs; +Cc: linux-kernel, syzkaller On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: > Hi, > > I've looked into this issue found by Syzbot and I made a patch: > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425b1163 Umm ... oops! Thanks for looking into this Tomas. > > > The autofs subsystem does not check that the "path" parameter is present > within the "param" struct passed by the userspace in case the > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a > path is always provided (though a path is not always present, as per how > the struct is defined: > https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_dev-ioct > l.h#L89). > Skipping the check provokes an oob read in "strlen", called by > "getname_kernel", in turn called by the autofs to assess the length of > the non-existing path. > > To solve it, modify the "validate_dev_ioctl" function to check also that > a path has been provided if the command is AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200 > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s > goto out; > } > } > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) > + return -EINVAL; My preference is to put the comment inside the else but ... There's another question, should the check be done in autofs_dev_ioctl_openmount() in the same way it's checked in other ioctls that need a path, such as in autofs_dev_ioctl_requester() and autofs_dev_ioctl_ismountpoint()? For consistency I'd say it should. > > err = 0; > out: > > > Tested and solves the issue on Linus' main git tree. > > Ian ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 1:10 ` Ian Kent @ 2018-07-02 1:42 ` Ian Kent 2018-07-02 8:31 ` tomas 0 siblings, 1 reply; 10+ messages in thread From: Ian Kent @ 2018-07-02 1:42 UTC (permalink / raw) To: tomas; +Cc: linux-kernel, syzkaller, autofs On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: > On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: > > Hi, > > > > I've looked into this issue found by Syzbot and I made a patch: > > > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425b116 > > 3 > > Umm ... oops! > > Thanks for looking into this Tomas. > > > > > > > The autofs subsystem does not check that the "path" parameter is present > > within the "param" struct passed by the userspace in case the > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a > > path is always provided (though a path is not always present, as per how > > the struct is defined: > > https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_dev-io > > ct > > l.h#L89). > > Skipping the check provokes an oob read in "strlen", called by > > "getname_kernel", in turn called by the autofs to assess the length of > > the non-existing path. > > > > To solve it, modify the "validate_dev_ioctl" function to check also that > > a path has been provided if the command is AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. > > > > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200 > > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 > > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s > > goto out; > > } > > } > > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ > > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) > > + return -EINVAL; > > My preference is to put the comment inside the else but ... > > There's another question, should the check be done in > autofs_dev_ioctl_openmount() in the same way it's checked in other > ioctls that need a path, such as in autofs_dev_ioctl_requester() > and autofs_dev_ioctl_ismountpoint()? > > For consistency I'd say it should. > > > > > err = 0; > > out: > > > > > > Tested and solves the issue on Linus' main git tree. > > > > Or perhaps this (not even compile tested) patch would be better? autofs - fix slab out of bounds read in getname_kernel() From: Ian Kent <raven@themaw.net> The autofs subsystem does not check that the "path" parameter is present for all cases where it is required when it is passed in via the "param" struct. In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD ioctl command. To solve it, modify validate_dev_ioctl() function to check that a path has been provided for ioctl commands that require it. --- fs/autofs/dev-ioctl.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c index ea4ca1445ab7..61c63715c3fb 100644 --- a/fs/autofs/dev-ioctl.c +++ b/fs/autofs/dev-ioctl.c @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) cmd); goto out; } + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { + err = -EINVAL; + goto out; } err = 0; @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, dev_t devid; int err = -ENOENT; - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { - err = -EINVAL; - goto out; - } + /* param->path has already been checked */ devid = sbi->sb->s_dev; @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp, unsigned int devid, magic; int err = -ENOENT; - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { - err = -EINVAL; - goto out; - } + /* param->path has already been checked */ name = param->path; type = param->ismountpoint.in.type; ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 1:42 ` Ian Kent @ 2018-07-02 8:31 ` tomas 2018-07-02 10:20 ` Ian Kent 0 siblings, 1 reply; 10+ messages in thread From: tomas @ 2018-07-02 8:31 UTC (permalink / raw) To: Ian Kent; +Cc: linux-kernel, syzkaller, autofs Hi Ian, you are welcome! yes your patch is much better. You should just put the "_IOC_NR" macro around "cmd" in the lines added to "validate_dev_ioctl" to make it work. Tomas On 07/02/2018 03:42 AM, Ian Kent wrote: > On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: >> On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: >>> Hi, >>> >>> I've looked into this issue found by Syzbot and I made a patch: >>> >>> https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425b116 >>> 3 >> Umm ... oops! >> >> Thanks for looking into this Tomas. >> >>> >>> The autofs subsystem does not check that the "path" parameter is present >>> within the "param" struct passed by the userspace in case the >>> AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a >>> path is always provided (though a path is not always present, as per how >>> the struct is defined: >>> https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_dev-io >>> ct >>> l.h#L89). >>> Skipping the check provokes an oob read in "strlen", called by >>> "getname_kernel", in turn called by the autofs to assess the length of >>> the non-existing path. >>> >>> To solve it, modify the "validate_dev_ioctl" function to check also that >>> a path has been provided if the command is AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. >>> >>> >>> --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200around >>> +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 >>> @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s >>> goto out; >>> } >>> } >>> + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ >>> + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) >>> + return -EINVAL; >> My preference is to put the comment inside the else but ... >> >> There's another question, should the check be done in >> autofs_dev_ioctl_openmount() in the same way it's checked in other >> ioctls that need a path, such as in autofs_dev_ioctl_requester() >> and autofs_dev_ioctl_ismountpoint()? >> >> For consistency I'd say it should. >> >>> >>> err = 0;You should just put the "_IOC_NR" directive around "cmd" in the lines added to "validate_dev_ioctl" to make it work. >>> out: >>> >>> >>> Tested and solves the issue on Linus' main git tree. >>> >>> > Or perhaps this (not even compile tested) patch would be better? > > autofs - fix slab out of bounds read in getname_kernel() > > From: Ian Kent <raven@themaw.net> > > The autofs subsystem does not check that the "path" parameter is > present for all cases where it is required when it is passed in > via the "param" struct. > > In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD > ioctl command. > > To solve it, modify validate_dev_ioctl() function to check that a > path has been provided for ioctl commands that require it. > --- > fs/autofs/dev-ioctl.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c > index ea4ca1445ab7..61c63715c3fb 100644 > --- a/fs/autofs/dev-ioctl.c > +++ b/fs/autofs/dev-ioctl.c > @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param) > cmd); > goto out; > } > + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || > + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || > + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { > + err = -EINVAL; > + goto out; > } > > err = 0; > @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, > dev_t devid; > int err = -ENOENT; > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > - err = -EINVAL; > - goto out; > - } > + /* param->path has already been checked */ > > devid = sbi->sb->s_dev; > > @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp, > unsigned int devid, magic; > int err = -ENOENT; > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > - err = -EINVAL; > - goto out; > - } > + /* param->path has already been checked */ > > name = param->path; > type = param->ismountpoint.in.type; ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 8:31 ` tomas @ 2018-07-02 10:20 ` Ian Kent 2018-07-02 11:55 ` tomas 0 siblings, 1 reply; 10+ messages in thread From: Ian Kent @ 2018-07-02 10:20 UTC (permalink / raw) To: tomas; +Cc: linux-kernel, syzkaller, autofs On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: > Hi Ian, > > you are welcome! > > yes your patch is much better. You should just put the "_IOC_NR" macro > around "cmd" in the lines added to "validate_dev_ioctl" to make it work. LOL, yes, that was a dumb mistake. I'll send it to Andrew Morton, after some fairly simple sanity testing, with both our Signed-off-by added. > > Tomas > > > On 07/02/2018 03:42 AM, Ian Kent wrote: > > On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: > > > On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: > > > > Hi, > > > > > > > > I've looked into this issue found by Syzbot and I made a patch: > > > > > > > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425 > > > > b116 > > > > 3 > > > > > > Umm ... oops! > > > > > > Thanks for looking into this Tomas. > > > > > > > > > > > The autofs subsystem does not check that the "path" parameter is present > > > > within the "param" struct passed by the userspace in case the > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a > > > > path is always provided (though a path is not always present, as per how > > > > the struct is defined: > > > > https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_de > > > > v-io > > > > ct > > > > l.h#L89). > > > > Skipping the check provokes an oob read in "strlen", called by > > > > "getname_kernel", in turn called by the autofs to assess the length of > > > > the non-existing path. > > > > > > > > To solve it, modify the "validate_dev_ioctl" function to check also that > > > > a path has been provided if the command is > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. > > > > > > > > > > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200around > > > > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 > > > > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s > > > > goto out; > > > > } > > > > } > > > > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ > > > > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) > > > > + return -EINVAL; > > > > > > My preference is to put the comment inside the else but ... > > > > > > There's another question, should the check be done in > > > autofs_dev_ioctl_openmount() in the same way it's checked in other > > > ioctls that need a path, such as in autofs_dev_ioctl_requester() > > > and autofs_dev_ioctl_ismountpoint()? > > > > > > For consistency I'd say it should. > > > > > > > > > > > err = 0;You should just put the "_IOC_NR" directive around "cmd" in > > > > the lines added to "validate_dev_ioctl" to make it work. > > > > out: > > > > > > > > > > > > Tested and solves the issue on Linus' main git tree. > > > > > > > > > > > > Or perhaps this (not even compile tested) patch would be better? > > > > autofs - fix slab out of bounds read in getname_kernel() > > > > From: Ian Kent <raven@themaw.net> > > > > The autofs subsystem does not check that the "path" parameter is > > present for all cases where it is required when it is passed in > > via the "param" struct. > > > > In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD > > ioctl command. > > > > To solve it, modify validate_dev_ioctl() function to check that a > > path has been provided for ioctl commands that require it. > > --- > > fs/autofs/dev-ioctl.c | 15 +++++++-------- > > 1 file changed, 7 insertions(+), 8 deletions(-) > > > > diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c > > index ea4ca1445ab7..61c63715c3fb 100644 > > --- a/fs/autofs/dev-ioctl.c > > +++ b/fs/autofs/dev-ioctl.c > > @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct > > autofs_dev_ioctl *param) > > cmd); > > goto out; > > } > > + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || > > + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || > > + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { > > + err = -EINVAL; > > + goto out; > > } > > > > err = 0; > > @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, > > dev_t devid; > > int err = -ENOENT; > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > - err = -EINVAL; > > - goto out; > > - } > > + /* param->path has already been checked */ > > > > devid = sbi->sb->s_dev; > > > > @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file > > *fp, > > unsigned int devid, magic; > > int err = -ENOENT; > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > - err = -EINVAL; > > - goto out; > > - } > > + /* param->path has already been checked */ > > > > name = param->path; > > type = param->ismountpoint.in.type; > > ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 10:20 ` Ian Kent @ 2018-07-02 11:55 ` tomas 2018-07-02 12:15 ` Dmitry Vyukov 0 siblings, 1 reply; 10+ messages in thread From: tomas @ 2018-07-02 11:55 UTC (permalink / raw) To: Ian Kent; +Cc: linux-kernel, syzkaller, autofs Yes, thanks. Please use my full name, Tomas Bortoli. Cheers On 07/02/2018 12:20 PM, Ian Kent wrote: > On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: >> Hi Ian, >> >> you are welcome! >> >> yes your patch is much better. You should just put the "_IOC_NR" macro >> around "cmd" in the lines added to "validate_dev_ioctl" to make it work. > LOL, yes, that was a dumb mistake. > > I'll send it to Andrew Morton, after some fairly simple sanity testing, > with both our Signed-off-by added. > >> Tomas >> >> >> On 07/02/2018 03:42 AM, Ian Kent wrote: >>> On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: >>>> On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: >>>>> Hi, >>>>> >>>>> I've looked into this issue found by Syzbot and I made a patch: >>>>> >>>>> https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425 >>>>> b116 >>>>> 3 >>>> Umm ... oops! >>>> >>>> Thanks for looking into this Tomas. >>>> >>>>> The autofs subsystem does not check that the "path" parameter is present >>>>> within the "param" struct passed by the userspace in case the >>>>> AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a >>>>> path is always provided (though a path is not always present, as per how >>>>> the struct is defined: >>>>> https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_de >>>>> v-io >>>>> ct >>>>> l.h#L89). >>>>> Skipping the check provokes an oob read in "strlen", called by >>>>> "getname_kernel", in turn called by the autofs to assess the length of >>>>> the non-existing path. >>>>> >>>>> To solve it, modify the "validate_dev_ioctl" function to check also that >>>>> a path has been provided if the command is >>>>> AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. >>>>> >>>>> >>>>> --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200around >>>>> +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 >>>>> @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s >>>>> goto out; >>>>> } >>>>> } >>>>> + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ >>>>> + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) >>>>> + return -EINVAL; >>>> My preference is to put the comment inside the else but ... >>>> >>>> There's another question, should the check be done in >>>> autofs_dev_ioctl_openmount() in the same way it's checked in other >>>> ioctls that need a path, such as in autofs_dev_ioctl_requester() >>>> and autofs_dev_ioctl_ismountpoint()? >>>> >>>> For consistency I'd say it should. >>>> >>>>> >>>>> err = 0;You should just put the "_IOC_NR" directive around "cmd" in >>>>> the lines added to "validate_dev_ioctl" to make it work. >>>>> out: >>>>> >>>>> >>>>> Tested and solves the issue on Linus' main git tree. >>>>> >>>>> >>> Or perhaps this (not even compile tested) patch would be better? >>> >>> autofs - fix slab out of bounds read in getname_kernel() >>> >>> From: Ian Kent <raven@themaw.net> >>> >>> The autofs subsystem does not check that the "path" parameter is >>> present for all cases where it is required when it is passed in >>> via the "param" struct. >>> >>> In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD >>> ioctl command. >>> >>> To solve it, modify validate_dev_ioctl() function to check that a >>> path has been provided for ioctl commands that require it. >>> --- >>> fs/autofs/dev-ioctl.c | 15 +++++++-------- >>> 1 file changed, 7 insertions(+), 8 deletions(-) >>> >>> diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c >>> index ea4ca1445ab7..61c63715c3fb 100644 >>> --- a/fs/autofs/dev-ioctl.c >>> +++ b/fs/autofs/dev-ioctl.c >>> @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct >>> autofs_dev_ioctl *param) >>> cmd); >>> goto out; >>> } >>> + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || >>> + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || >>> + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { >>> + err = -EINVAL; >>> + goto out; >>> } >>> >>> err = 0; >>> @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, >>> dev_t devid; >>> int err = -ENOENT; >>> >>> - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >>> - err = -EINVAL; >>> - goto out; >>> - } >>> + /* param->path has already been checked */ >>> >>> devid = sbi->sb->s_dev; >>> >>> @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file >>> *fp, >>> unsigned int devid, magic; >>> int err = -ENOENT; >>> >>> - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >>> - err = -EINVAL; >>> - goto out; >>> - } >>> + /* param->path has already been checked */ >>> >>> name = param->path; >>> type = param->ismountpoint.in.type; >> ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 11:55 ` tomas @ 2018-07-02 12:15 ` Dmitry Vyukov 2018-07-03 1:34 ` Ian Kent 0 siblings, 1 reply; 10+ messages in thread From: Dmitry Vyukov @ 2018-07-02 12:15 UTC (permalink / raw) To: tomas; +Cc: Ian Kent, LKML, syzkaller, autofs On Mon, Jul 2, 2018 at 1:55 PM, tomas <tomasbortoli@gmail.com> wrote: > Yes, thanks. Please use my full name, Tomas Bortoli. Please also include: Reported-by: syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com from the original bug report. This this help to keep automatic testing process running. Thanks > > On 07/02/2018 12:20 PM, Ian Kent wrote: >> On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: >>> Hi Ian, >>> >>> you are welcome! >>> >>> yes your patch is much better. You should just put the "_IOC_NR" macro >>> around "cmd" in the lines added to "validate_dev_ioctl" to make it work. >> LOL, yes, that was a dumb mistake. >> >> I'll send it to Andrew Morton, after some fairly simple sanity testing, >> with both our Signed-off-by added. >> >>> Tomas >>> >>> >>> On 07/02/2018 03:42 AM, Ian Kent wrote: >>>> On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: >>>>> On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: >>>>>> Hi, >>>>>> >>>>>> I've looked into this issue found by Syzbot and I made a patch: >>>>>> >>>>>> https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f97208ae425 >>>>>> b116 >>>>>> 3 >>>>> Umm ... oops! >>>>> >>>>> Thanks for looking into this Tomas. >>>>> >>>>>> The autofs subsystem does not check that the "path" parameter is present >>>>>> within the "param" struct passed by the userspace in case the >>>>>> AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it assumes a >>>>>> path is always provided (though a path is not always present, as per how >>>>>> the struct is defined: >>>>>> https://github.com/torvalds/linux/blob/master/include/uapi/linux/auto_de >>>>>> v-io >>>>>> ct >>>>>> l.h#L89). >>>>>> Skipping the check provokes an oob read in "strlen", called by >>>>>> "getname_kernel", in turn called by the autofs to assess the length of >>>>>> the non-existing path. >>>>>> >>>>>> To solve it, modify the "validate_dev_ioctl" function to check also that >>>>>> a path has been provided if the command is >>>>>> AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. >>>>>> >>>>>> >>>>>> --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 +0200around >>>>>> +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 >>>>>> @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s >>>>>> goto out; >>>>>> } >>>>>> } >>>>>> + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ >>>>>> + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) >>>>>> + return -EINVAL; >>>>> My preference is to put the comment inside the else but ... >>>>> >>>>> There's another question, should the check be done in >>>>> autofs_dev_ioctl_openmount() in the same way it's checked in other >>>>> ioctls that need a path, such as in autofs_dev_ioctl_requester() >>>>> and autofs_dev_ioctl_ismountpoint()? >>>>> >>>>> For consistency I'd say it should. >>>>> >>>>>> >>>>>> err = 0;You should just put the "_IOC_NR" directive around "cmd" in >>>>>> the lines added to "validate_dev_ioctl" to make it work. >>>>>> out: >>>>>> >>>>>> >>>>>> Tested and solves the issue on Linus' main git tree. >>>>>> >>>>>> >>>> Or perhaps this (not even compile tested) patch would be better? >>>> >>>> autofs - fix slab out of bounds read in getname_kernel() >>>> >>>> From: Ian Kent <raven@themaw.net> >>>> >>>> The autofs subsystem does not check that the "path" parameter is >>>> present for all cases where it is required when it is passed in >>>> via the "param" struct. >>>> >>>> In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD >>>> ioctl command. >>>> >>>> To solve it, modify validate_dev_ioctl() function to check that a >>>> path has been provided for ioctl commands that require it. >>>> --- >>>> fs/autofs/dev-ioctl.c | 15 +++++++-------- >>>> 1 file changed, 7 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c >>>> index ea4ca1445ab7..61c63715c3fb 100644 >>>> --- a/fs/autofs/dev-ioctl.c >>>> +++ b/fs/autofs/dev-ioctl.c >>>> @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct >>>> autofs_dev_ioctl *param) >>>> cmd); >>>> goto out; >>>> } >>>> + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || >>>> + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || >>>> + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { >>>> + err = -EINVAL; >>>> + goto out; >>>> } >>>> >>>> err = 0; >>>> @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, >>>> dev_t devid; >>>> int err = -ENOENT; >>>> >>>> - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >>>> - err = -EINVAL; >>>> - goto out; >>>> - } >>>> + /* param->path has already been checked */ >>>> >>>> devid = sbi->sb->s_dev; >>>> >>>> @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file >>>> *fp, >>>> unsigned int devid, magic; >>>> int err = -ENOENT; >>>> >>>> - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >>>> - err = -EINVAL; >>>> - goto out; >>>> - } >>>> + /* param->path has already been checked */ >>>> >>>> name = param->path; >>>> type = param->ismountpoint.in.type; >>> > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-02 12:15 ` Dmitry Vyukov @ 2018-07-03 1:34 ` Ian Kent 2018-07-03 5:48 ` Dmitry Vyukov 0 siblings, 1 reply; 10+ messages in thread From: Ian Kent @ 2018-07-03 1:34 UTC (permalink / raw) To: Dmitry Vyukov, tomas; +Cc: LKML, syzkaller, autofs On Mon, 2018-07-02 at 14:15 +0200, Dmitry Vyukov wrote: > On Mon, Jul 2, 2018 at 1:55 PM, tomas <tomasbortoli@gmail.com> wrote: > > Yes, thanks. Please use my full name, Tomas Bortoli. > > > Please also include: > > Reported-by: syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com Done. > > from the original bug report. This this help to keep automatic testing > process running. Umm ... should I include this email address on the actual cc when submitting the patch? > > Thanks > > > > > > On 07/02/2018 12:20 PM, Ian Kent wrote: > > > On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: > > > > Hi Ian, > > > > > > > > you are welcome! > > > > > > > > yes your patch is much better. You should just put the "_IOC_NR" macro > > > > around "cmd" in the lines added to "validate_dev_ioctl" to make it work. > > > > > > LOL, yes, that was a dumb mistake. > > > > > > I'll send it to Andrew Morton, after some fairly simple sanity testing, > > > with both our Signed-off-by added. > > > > > > > Tomas > > > > > > > > > > > > On 07/02/2018 03:42 AM, Ian Kent wrote: > > > > > On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: > > > > > > On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: > > > > > > > Hi, > > > > > > > > > > > > > > I've looked into this issue found by Syzbot and I made a patch: > > > > > > > > > > > > > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f9720 > > > > > > > 8ae425 > > > > > > > b116 > > > > > > > 3 > > > > > > > > > > > > Umm ... oops! > > > > > > > > > > > > Thanks for looking into this Tomas. > > > > > > > > > > > > > The autofs subsystem does not check that the "path" parameter is > > > > > > > present > > > > > > > within the "param" struct passed by the userspace in case the > > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it > > > > > > > assumes a > > > > > > > path is always provided (though a path is not always present, as > > > > > > > per how > > > > > > > the struct is defined: > > > > > > > https://github.com/torvalds/linux/blob/master/include/uapi/linux/a > > > > > > > uto_de > > > > > > > v-io > > > > > > > ct > > > > > > > l.h#L89). > > > > > > > Skipping the check provokes an oob read in "strlen", called by > > > > > > > "getname_kernel", in turn called by the autofs to assess the > > > > > > > length of > > > > > > > the non-existing path. > > > > > > > > > > > > > > To solve it, modify the "validate_dev_ioctl" function to check > > > > > > > also that > > > > > > > a path has been provided if the command is > > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. > > > > > > > > > > > > > > > > > > > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 > > > > > > > +0200around > > > > > > > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 > > > > > > > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s > > > > > > > goto out; > > > > > > > } > > > > > > > } > > > > > > > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ > > > > > > > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) > > > > > > > + return -EINVAL; > > > > > > > > > > > > My preference is to put the comment inside the else but ... > > > > > > > > > > > > There's another question, should the check be done in > > > > > > autofs_dev_ioctl_openmount() in the same way it's checked in other > > > > > > ioctls that need a path, such as in autofs_dev_ioctl_requester() > > > > > > and autofs_dev_ioctl_ismountpoint()? > > > > > > > > > > > > For consistency I'd say it should. > > > > > > > > > > > > > > > > > > > > err = 0;You should just put the "_IOC_NR" directive around > > > > > > > "cmd" in > > > > > > > the lines added to "validate_dev_ioctl" to make it work. > > > > > > > out: > > > > > > > > > > > > > > > > > > > > > Tested and solves the issue on Linus' main git tree. > > > > > > > > > > > > > > > > > > > > > > > > Or perhaps this (not even compile tested) patch would be better? > > > > > > > > > > autofs - fix slab out of bounds read in getname_kernel() > > > > > > > > > > From: Ian Kent <raven@themaw.net> > > > > > > > > > > The autofs subsystem does not check that the "path" parameter is > > > > > present for all cases where it is required when it is passed in > > > > > via the "param" struct. > > > > > > > > > > In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD > > > > > ioctl command. > > > > > > > > > > To solve it, modify validate_dev_ioctl() function to check that a > > > > > path has been provided for ioctl commands that require it. > > > > > --- > > > > > fs/autofs/dev-ioctl.c | 15 +++++++-------- > > > > > 1 file changed, 7 insertions(+), 8 deletions(-) > > > > > > > > > > diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c > > > > > index ea4ca1445ab7..61c63715c3fb 100644 > > > > > --- a/fs/autofs/dev-ioctl.c > > > > > +++ b/fs/autofs/dev-ioctl.c > > > > > @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct > > > > > autofs_dev_ioctl *param) > > > > > cmd); > > > > > goto out; > > > > > } > > > > > + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || > > > > > + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || > > > > > + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { > > > > > + err = -EINVAL; > > > > > + goto out; > > > > > } > > > > > > > > > > err = 0; > > > > > @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file > > > > > *fp, > > > > > dev_t devid; > > > > > int err = -ENOENT; > > > > > > > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > > > > - err = -EINVAL; > > > > > - goto out; > > > > > - } > > > > > + /* param->path has already been checked */ > > > > > > > > > > devid = sbi->sb->s_dev; > > > > > > > > > > @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct > > > > > file > > > > > *fp, > > > > > unsigned int devid, magic; > > > > > int err = -ENOENT; > > > > > > > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > > > > - err = -EINVAL; > > > > > - goto out; > > > > > - } > > > > > + /* param->path has already been checked */ > > > > > > > > > > name = param->path; > > > > > type = param->ismountpoint.in.type; > > > > -- > > You received this message because you are subscribed to the Google Groups > > "syzkaller" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to syzkaller+unsubscribe@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-03 1:34 ` Ian Kent @ 2018-07-03 5:48 ` Dmitry Vyukov 2018-07-03 6:40 ` Ian Kent 0 siblings, 1 reply; 10+ messages in thread From: Dmitry Vyukov @ 2018-07-03 5:48 UTC (permalink / raw) To: Ian Kent; +Cc: tomas, LKML, syzkaller, autofs On Tue, Jul 3, 2018 at 3:34 AM, Ian Kent <raven@themaw.net> wrote: > On Mon, 2018-07-02 at 14:15 +0200, Dmitry Vyukov wrote: >> On Mon, Jul 2, 2018 at 1:55 PM, tomas <tomasbortoli@gmail.com> wrote: >> > Yes, thanks. Please use my full name, Tomas Bortoli. >> >> >> Please also include: >> >> Reported-by: syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com > > Done. > >> >> from the original bug report. This this help to keep automatic testing >> process running. > > Umm ... should I include this email address on the actual cc when > submitting the patch? It does not matter. It's a real email address too, so CCing it is fine. So if git does it automatically (does it?) then just go with it. If you are doing it manually, then it's not necessary to add it to CC. syzbot will scrape git log later to discover the tag and mark the bug fixed. Thanks >> > On 07/02/2018 12:20 PM, Ian Kent wrote: >> > > On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: >> > > > Hi Ian, >> > > > >> > > > you are welcome! >> > > > >> > > > yes your patch is much better. You should just put the "_IOC_NR" macro >> > > > around "cmd" in the lines added to "validate_dev_ioctl" to make it work. >> > > >> > > LOL, yes, that was a dumb mistake. >> > > >> > > I'll send it to Andrew Morton, after some fairly simple sanity testing, >> > > with both our Signed-off-by added. >> > > >> > > > Tomas >> > > > >> > > > >> > > > On 07/02/2018 03:42 AM, Ian Kent wrote: >> > > > > On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: >> > > > > > On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: >> > > > > > > Hi, >> > > > > > > >> > > > > > > I've looked into this issue found by Syzbot and I made a patch: >> > > > > > > >> > > > > > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f9720 >> > > > > > > 8ae425 >> > > > > > > b116 >> > > > > > > 3 >> > > > > > >> > > > > > Umm ... oops! >> > > > > > >> > > > > > Thanks for looking into this Tomas. >> > > > > > >> > > > > > > The autofs subsystem does not check that the "path" parameter is >> > > > > > > present >> > > > > > > within the "param" struct passed by the userspace in case the >> > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it >> > > > > > > assumes a >> > > > > > > path is always provided (though a path is not always present, as >> > > > > > > per how >> > > > > > > the struct is defined: >> > > > > > > https://github.com/torvalds/linux/blob/master/include/uapi/linux/a >> > > > > > > uto_de >> > > > > > > v-io >> > > > > > > ct >> > > > > > > l.h#L89). >> > > > > > > Skipping the check provokes an oob read in "strlen", called by >> > > > > > > "getname_kernel", in turn called by the autofs to assess the >> > > > > > > length of >> > > > > > > the non-existing path. >> > > > > > > >> > > > > > > To solve it, modify the "validate_dev_ioctl" function to check >> > > > > > > also that >> > > > > > > a path has been provided if the command is >> > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. >> > > > > > > >> > > > > > > >> > > > > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 >> > > > > > > +0200around >> > > > > > > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 +0200 >> > > > > > > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s >> > > > > > > goto out; >> > > > > > > } >> > > > > > > } >> > > > > > > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ >> > > > > > > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) >> > > > > > > + return -EINVAL; >> > > > > > >> > > > > > My preference is to put the comment inside the else but ... >> > > > > > >> > > > > > There's another question, should the check be done in >> > > > > > autofs_dev_ioctl_openmount() in the same way it's checked in other >> > > > > > ioctls that need a path, such as in autofs_dev_ioctl_requester() >> > > > > > and autofs_dev_ioctl_ismountpoint()? >> > > > > > >> > > > > > For consistency I'd say it should. >> > > > > > >> > > > > > > >> > > > > > > err = 0;You should just put the "_IOC_NR" directive around >> > > > > > > "cmd" in >> > > > > > > the lines added to "validate_dev_ioctl" to make it work. >> > > > > > > out: >> > > > > > > >> > > > > > > >> > > > > > > Tested and solves the issue on Linus' main git tree. >> > > > > > > >> > > > > > > >> > > > > >> > > > > Or perhaps this (not even compile tested) patch would be better? >> > > > > >> > > > > autofs - fix slab out of bounds read in getname_kernel() >> > > > > >> > > > > From: Ian Kent <raven@themaw.net> >> > > > > >> > > > > The autofs subsystem does not check that the "path" parameter is >> > > > > present for all cases where it is required when it is passed in >> > > > > via the "param" struct. >> > > > > >> > > > > In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD >> > > > > ioctl command. >> > > > > >> > > > > To solve it, modify validate_dev_ioctl() function to check that a >> > > > > path has been provided for ioctl commands that require it. >> > > > > --- >> > > > > fs/autofs/dev-ioctl.c | 15 +++++++-------- >> > > > > 1 file changed, 7 insertions(+), 8 deletions(-) >> > > > > >> > > > > diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c >> > > > > index ea4ca1445ab7..61c63715c3fb 100644 >> > > > > --- a/fs/autofs/dev-ioctl.c >> > > > > +++ b/fs/autofs/dev-ioctl.c >> > > > > @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct >> > > > > autofs_dev_ioctl *param) >> > > > > cmd); >> > > > > goto out; >> > > > > } >> > > > > + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || >> > > > > + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || >> > > > > + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { >> > > > > + err = -EINVAL; >> > > > > + goto out; >> > > > > } >> > > > > >> > > > > err = 0; >> > > > > @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct file >> > > > > *fp, >> > > > > dev_t devid; >> > > > > int err = -ENOENT; >> > > > > >> > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >> > > > > - err = -EINVAL; >> > > > > - goto out; >> > > > > - } >> > > > > + /* param->path has already been checked */ >> > > > > >> > > > > devid = sbi->sb->s_dev; >> > > > > >> > > > > @@ -521,10 +523,7 @@ static int autofs_dev_ioctl_ismountpoint(struct >> > > > > file >> > > > > *fp, >> > > > > unsigned int devid, magic; >> > > > > int err = -ENOENT; >> > > > > >> > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { >> > > > > - err = -EINVAL; >> > > > > - goto out; >> > > > > - } >> > > > > + /* param->path has already been checked */ >> > > > > >> > > > > name = param->path; >> > > > > type = param->ismountpoint.in.type; >> > >> > -- >> > You received this message because you are subscribed to the Google Groups >> > "syzkaller" group. >> > To unsubscribe from this group and stop receiving emails from it, send an >> > email to syzkaller+unsubscribe@googlegroups.com. >> > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel 2018-07-03 5:48 ` Dmitry Vyukov @ 2018-07-03 6:40 ` Ian Kent 0 siblings, 0 replies; 10+ messages in thread From: Ian Kent @ 2018-07-03 6:40 UTC (permalink / raw) To: Dmitry Vyukov; +Cc: tomas, LKML, syzkaller, autofs On Tue, 2018-07-03 at 07:48 +0200, Dmitry Vyukov wrote: > On Tue, Jul 3, 2018 at 3:34 AM, Ian Kent <raven@themaw.net> wrote: > > On Mon, 2018-07-02 at 14:15 +0200, Dmitry Vyukov wrote: > > > On Mon, Jul 2, 2018 at 1:55 PM, tomas <tomasbortoli@gmail.com> wrote: > > > > Yes, thanks. Please use my full name, Tomas Bortoli. > > > > > > > > > Please also include: > > > > > > Reported-by: syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com > > > > Done. > > > > > > > > from the original bug report. This this help to keep automatic testing > > > process running. > > > > Umm ... should I include this email address on the actual cc when > > submitting the patch? > > It does not matter. It's a real email address too, so CCing it is > fine. So if git does it automatically (does it?) then just go with it. > If you are doing it manually, then it's not necessary to add it to CC. Right, I thought a mail would probably be sent at merge time (or perhaps when Andrew adds it to mmotm) so I didn't think it sensible to cc when submitting. Personally I use StGIT to manage patches and that will only send to addresses specified when patches are emailed. > > syzbot will scrape git log later to discover the tag and mark the bug fixed. > > Thanks > > > > > On 07/02/2018 12:20 PM, Ian Kent wrote: > > > > > On Mon, 2018-07-02 at 10:31 +0200, tomas wrote: > > > > > > Hi Ian, > > > > > > > > > > > > you are welcome! > > > > > > > > > > > > yes your patch is much better. You should just put the "_IOC_NR" > > > > > > macro > > > > > > around "cmd" in the lines added to "validate_dev_ioctl" to make it > > > > > > work. > > > > > > > > > > LOL, yes, that was a dumb mistake. > > > > > > > > > > I'll send it to Andrew Morton, after some fairly simple sanity > > > > > testing, > > > > > with both our Signed-off-by added. > > > > > > > > > > > Tomas > > > > > > > > > > > > > > > > > > On 07/02/2018 03:42 AM, Ian Kent wrote: > > > > > > > On Mon, 2018-07-02 at 09:10 +0800, Ian Kent wrote: > > > > > > > > On Mon, 2018-07-02 at 00:04 +0200, tomas wrote: > > > > > > > > > Hi, > > > > > > > > > > > > > > > > > > I've looked into this issue found by Syzbot and I made a > > > > > > > > > patch: > > > > > > > > > > > > > > > > > > https://syzkaller.appspot.com/bug?id=d03abd8b42847f7f69b1d1d7f > > > > > > > > > 9720 > > > > > > > > > 8ae425 > > > > > > > > > b116 > > > > > > > > > 3 > > > > > > > > > > > > > > > > Umm ... oops! > > > > > > > > > > > > > > > > Thanks for looking into this Tomas. > > > > > > > > > > > > > > > > > The autofs subsystem does not check that the "path" parameter > > > > > > > > > is > > > > > > > > > present > > > > > > > > > within the "param" struct passed by the userspace in case the > > > > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD command is passed. Indeed, it > > > > > > > > > assumes a > > > > > > > > > path is always provided (though a path is not always present, > > > > > > > > > as > > > > > > > > > per how > > > > > > > > > the struct is defined: > > > > > > > > > https://github.com/torvalds/linux/blob/master/include/uapi/lin > > > > > > > > > ux/a > > > > > > > > > uto_de > > > > > > > > > v-io > > > > > > > > > ct > > > > > > > > > l.h#L89). > > > > > > > > > Skipping the check provokes an oob read in "strlen", called by > > > > > > > > > "getname_kernel", in turn called by the autofs to assess the > > > > > > > > > length of > > > > > > > > > the non-existing path. > > > > > > > > > > > > > > > > > > To solve it, modify the "validate_dev_ioctl" function to check > > > > > > > > > also that > > > > > > > > > a path has been provided if the command is > > > > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD. > > > > > > > > > > > > > > > > > > > > > > > > > > > --- b/fs/autofs/dev-ioctl.c 2018-07-01 23:10:16.059728621 > > > > > > > > > +0200around > > > > > > > > > +++ a/fs/autofs/dev-ioctl.c 2018-07-01 23:10:24.311792133 > > > > > > > > > +0200 > > > > > > > > > @@ -136,6 +136,9 @@ static int validate_dev_ioctl(int cmd, s > > > > > > > > > goto out; > > > > > > > > > } > > > > > > > > > } > > > > > > > > > + /* AUTOFS_DEV_IOCTL_OPENMOUNT_CMD without path */ > > > > > > > > > + else if(_IOC_NR(cmd) == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD) > > > > > > > > > + return -EINVAL; > > > > > > > > > > > > > > > > My preference is to put the comment inside the else but ... > > > > > > > > > > > > > > > > There's another question, should the check be done in > > > > > > > > autofs_dev_ioctl_openmount() in the same way it's checked in > > > > > > > > other > > > > > > > > ioctls that need a path, such as in autofs_dev_ioctl_requester() > > > > > > > > and autofs_dev_ioctl_ismountpoint()? > > > > > > > > > > > > > > > > For consistency I'd say it should. > > > > > > > > > > > > > > > > > > > > > > > > > > err = 0;You should just put the "_IOC_NR" directive > > > > > > > > > around > > > > > > > > > "cmd" in > > > > > > > > > the lines added to "validate_dev_ioctl" to make it work. > > > > > > > > > out: > > > > > > > > > > > > > > > > > > > > > > > > > > > Tested and solves the issue on Linus' main git tree. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Or perhaps this (not even compile tested) patch would be better? > > > > > > > > > > > > > > autofs - fix slab out of bounds read in getname_kernel() > > > > > > > > > > > > > > From: Ian Kent <raven@themaw.net> > > > > > > > > > > > > > > The autofs subsystem does not check that the "path" parameter is > > > > > > > present for all cases where it is required when it is passed in > > > > > > > via the "param" struct. > > > > > > > > > > > > > > In particular it isn't checked for the > > > > > > > AUTOFS_DEV_IOCTL_OPENMOUNT_CMD > > > > > > > ioctl command. > > > > > > > > > > > > > > To solve it, modify validate_dev_ioctl() function to check that a > > > > > > > path has been provided for ioctl commands that require it. > > > > > > > --- > > > > > > > fs/autofs/dev-ioctl.c | 15 +++++++-------- > > > > > > > 1 file changed, 7 insertions(+), 8 deletions(-) > > > > > > > > > > > > > > diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c > > > > > > > index ea4ca1445ab7..61c63715c3fb 100644 > > > > > > > --- a/fs/autofs/dev-ioctl.c > > > > > > > +++ b/fs/autofs/dev-ioctl.c > > > > > > > @@ -135,6 +135,11 @@ static int validate_dev_ioctl(int cmd, struct > > > > > > > autofs_dev_ioctl *param) > > > > > > > cmd); > > > > > > > goto out; > > > > > > > } > > > > > > > + } else if (cmd == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD || > > > > > > > + cmd == AUTOFS_DEV_IOCTL_REQUESTER_CMD || > > > > > > > + cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) { > > > > > > > + err = -EINVAL; > > > > > > > + goto out; > > > > > > > } > > > > > > > > > > > > > > err = 0; > > > > > > > @@ -433,10 +438,7 @@ static int autofs_dev_ioctl_requester(struct > > > > > > > file > > > > > > > *fp, > > > > > > > dev_t devid; > > > > > > > int err = -ENOENT; > > > > > > > > > > > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > > > > > > - err = -EINVAL; > > > > > > > - goto out; > > > > > > > - } > > > > > > > + /* param->path has already been checked */ > > > > > > > > > > > > > > devid = sbi->sb->s_dev; > > > > > > > > > > > > > > @@ -521,10 +523,7 @@ static int > > > > > > > autofs_dev_ioctl_ismountpoint(struct > > > > > > > file > > > > > > > *fp, > > > > > > > unsigned int devid, magic; > > > > > > > int err = -ENOENT; > > > > > > > > > > > > > > - if (param->size <= AUTOFS_DEV_IOCTL_SIZE) { > > > > > > > - err = -EINVAL; > > > > > > > - goto out; > > > > > > > - } > > > > > > > + /* param->path has already been checked */ > > > > > > > > > > > > > > name = param->path; > > > > > > > type = param->ismountpoint.in.type; > > > > > > > > -- > > > > You received this message because you are subscribed to the Google > > > > Groups > > > > "syzkaller" group. > > > > To unsubscribe from this group and stop receiving emails from it, send > > > > an > > > > email to syzkaller+unsubscribe@googlegroups.com. > > > > For more options, visit https://groups.google.com/d/optout. > > > > -- > > You received this message because you are subscribed to the Google Groups > > "syzkaller" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to syzkaller+unsubscribe@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2018-07-03 6:40 UTC | newest] Thread overview: 10+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2018-07-01 22:04 [PATCH upstream] KASAN: slab-out-of-bounds Read in getname_kernel tomas 2018-07-02 1:10 ` Ian Kent 2018-07-02 1:42 ` Ian Kent 2018-07-02 8:31 ` tomas 2018-07-02 10:20 ` Ian Kent 2018-07-02 11:55 ` tomas 2018-07-02 12:15 ` Dmitry Vyukov 2018-07-03 1:34 ` Ian Kent 2018-07-03 5:48 ` Dmitry Vyukov 2018-07-03 6:40 ` Ian Kent
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