* [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations
@ 2007-08-30 15:06 Jeff Layton
2007-08-30 16:03 ` Peter Staubach
2007-08-30 16:33 ` Christoph Hellwig
0 siblings, 2 replies; 3+ messages in thread
From: Jeff Layton @ 2007-08-30 15:06 UTC (permalink / raw)
To: linux-kernel, linux-fsdevel; +Cc: nfs, linux-cifs-client
Make notify_change not clear the ATTR_KILL_S*ID bits in the ia_vaid that
gets passed to the setattr inode operation. This allows the filesystems
to reinterpret whether this mode change is simply intended to clear the
setuid/setgid bits.
This means that notify_change should never be called with both ATTR_MODE
and either of the ATTR_KILL_S*ID bits set, since the filesystem would
have no way to know what part of the mode change was intentional. If
it is called this way, consider it a BUG().
Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/attr.c | 22 ++++++++++++----------
1 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/attr.c b/fs/attr.c
index ae58bd3..f98d10c 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -103,12 +103,11 @@ EXPORT_SYMBOL(inode_setattr);
int notify_change(struct dentry * dentry, struct iattr * attr)
{
struct inode *inode = dentry->d_inode;
- mode_t mode;
+ mode_t mode = inode->i_mode;
int error;
struct timespec now;
unsigned int ia_valid = attr->ia_valid;
- mode = inode->i_mode;
now = current_fs_time(inode->i_sb);
attr->ia_ctime = now;
@@ -125,18 +124,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
if (error)
return error;
}
+
+ /*
+ * It's not valid to pass an iattr with both ATTR_MODE and
+ * ATTR_KILL_S*ID set.
+ */
+ if (ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID) && ia_valid & ATTR_MODE)
+ BUG();
+
if (ia_valid & ATTR_KILL_SUID) {
- attr->ia_valid &= ~ATTR_KILL_SUID;
if (mode & S_ISUID) {
- if (!(ia_valid & ATTR_MODE)) {
- ia_valid = attr->ia_valid |= ATTR_MODE;
- attr->ia_mode = inode->i_mode;
- }
- attr->ia_mode &= ~S_ISUID;
+ ia_valid = attr->ia_valid |= ATTR_MODE;
+ attr->ia_mode = (inode->i_mode & ~S_ISUID);
}
}
if (ia_valid & ATTR_KILL_SGID) {
- attr->ia_valid &= ~ ATTR_KILL_SGID;
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
if (!(ia_valid & ATTR_MODE)) {
ia_valid = attr->ia_valid |= ATTR_MODE;
@@ -145,7 +147,7 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
attr->ia_mode &= ~S_ISGID;
}
}
- if (!attr->ia_valid)
+ if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
return 0;
if (ia_valid & ATTR_SIZE)
--
1.5.2.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations
2007-08-30 15:06 [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations Jeff Layton
@ 2007-08-30 16:03 ` Peter Staubach
2007-08-30 16:33 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Peter Staubach @ 2007-08-30 16:03 UTC (permalink / raw)
To: Jeff Layton; +Cc: linux-fsdevel, linux-cifs-client, nfs, linux-kernel
Jeff Layton wrote:
> Make notify_change not clear the ATTR_KILL_S*ID bits in the ia_vaid that
> gets passed to the setattr inode operation. This allows the filesystems
> to reinterpret whether this mode change is simply intended to clear the
> setuid/setgid bits.
>
> This means that notify_change should never be called with both ATTR_MODE
> and either of the ATTR_KILL_S*ID bits set, since the filesystem would
> have no way to know what part of the mode change was intentional. If
> it is called this way, consider it a BUG().
>
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
> fs/attr.c | 22 ++++++++++++----------
> 1 files changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/fs/attr.c b/fs/attr.c
> index ae58bd3..f98d10c 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -103,12 +103,11 @@ EXPORT_SYMBOL(inode_setattr);
> int notify_change(struct dentry * dentry, struct iattr * attr)
> {
> struct inode *inode = dentry->d_inode;
> - mode_t mode;
> + mode_t mode = inode->i_mode;
> int error;
> struct timespec now;
> unsigned int ia_valid = attr->ia_valid;
>
> - mode = inode->i_mode;
> now = current_fs_time(inode->i_sb);
>
> attr->ia_ctime = now;
> @@ -125,18 +124,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
> if (error)
> return error;
> }
> +
> + /*
> + * It's not valid to pass an iattr with both ATTR_MODE and
> + * ATTR_KILL_S*ID set.
> + */
> + if (ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID) && ia_valid & ATTR_MODE)
>
If you would, please add some parentheses to show and make
explicit what the bindings are. This is:
if ((ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) &&
(ia_valid & ATTR_MODE))
Thanx...
ps
> + BUG();
> +
> if (ia_valid & ATTR_KILL_SUID) {
> - attr->ia_valid &= ~ATTR_KILL_SUID;
> if (mode & S_ISUID) {
> - if (!(ia_valid & ATTR_MODE)) {
> - ia_valid = attr->ia_valid |= ATTR_MODE;
> - attr->ia_mode = inode->i_mode;
> - }
> - attr->ia_mode &= ~S_ISUID;
> + ia_valid = attr->ia_valid |= ATTR_MODE;
> + attr->ia_mode = (inode->i_mode & ~S_ISUID);
> }
> }
> if (ia_valid & ATTR_KILL_SGID) {
> - attr->ia_valid &= ~ ATTR_KILL_SGID;
> if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
> if (!(ia_valid & ATTR_MODE)) {
> ia_valid = attr->ia_valid |= ATTR_MODE;
> @@ -145,7 +147,7 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
> attr->ia_mode &= ~S_ISGID;
> }
> }
> - if (!attr->ia_valid)
> + if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
> return 0;
>
> if (ia_valid & ATTR_SIZE)
>
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations
2007-08-30 15:06 [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations Jeff Layton
2007-08-30 16:03 ` Peter Staubach
@ 2007-08-30 16:33 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2007-08-30 16:33 UTC (permalink / raw)
To: Jeff Layton; +Cc: linux-kernel, linux-fsdevel, linux-cifs-client, nfs
On Thu, Aug 30, 2007 at 11:06:38AM -0400, Jeff Layton wrote:
> Make notify_change not clear the ATTR_KILL_S*ID bits in the ia_vaid that
> gets passed to the setattr inode operation. This allows the filesystems
> to reinterpret whether this mode change is simply intended to clear the
> setuid/setgid bits.
>
> This means that notify_change should never be called with both ATTR_MODE
> and either of the ATTR_KILL_S*ID bits set, since the filesystem would
> have no way to know what part of the mode change was intentional. If
> it is called this way, consider it a BUG().
This one looks fine to, but you'll probably need an additional patch
to ecryptfs so it clears ATTR_MODE before calling notify_change for
the lower inode.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2007-08-30 15:06 [PATCH 1/3] VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations Jeff Layton
2007-08-30 16:03 ` Peter Staubach
2007-08-30 16:33 ` Christoph Hellwig
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