* [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling
@ 2010-06-01 13:10 David Howells
2010-06-02 2:40 ` Takuya Yoshikawa
2010-06-02 8:20 ` Paul Mundt
0 siblings, 2 replies; 6+ messages in thread
From: David Howells @ 2010-06-01 13:10 UTC (permalink / raw)
To: torvalds, akpm
Cc: linux-kernel, Takuya Yoshikawa, David Howells, Mike Frysinger,
Alexander Viro, Andrew Morton, Daisuke HATAYAMA, Paul Mundt
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
clear_user() returns the number of bytes that could not be copied rather than
an error code. So we should return -EFAULT rather than directly returning the
results.
Without this patch, positive values may be returned to elf_fdpic_map_file()
and the following error handlings do not function as expected.
1.
ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
if (ret < 0)
return ret;
2.
ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
if (ret < 0)
return ret;
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
CC: Paul Mundt <lethal@linux-sh.org>
---
fs/binfmt_elf_fdpic.c | 26 +++++++++++---------------
1 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 2c5f9a0..63039ed 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -990,10 +990,9 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
/* clear any space allocated but not loaded */
if (phdr->p_filesz < phdr->p_memsz) {
- ret = clear_user((void *) (seg->addr + phdr->p_filesz),
- phdr->p_memsz - phdr->p_filesz);
- if (ret)
- return ret;
+ if (clear_user((void *) (seg->addr + phdr->p_filesz),
+ phdr->p_memsz - phdr->p_filesz))
+ return -EFAULT;
}
if (mm) {
@@ -1027,7 +1026,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
struct elf32_fdpic_loadseg *seg;
struct elf32_phdr *phdr;
unsigned long load_addr, delta_vaddr;
- int loop, dvset, ret;
+ int loop, dvset;
load_addr = params->load_addr;
delta_vaddr = 0;
@@ -1127,9 +1126,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
* PT_LOAD */
if (prot & PROT_WRITE && disp > 0) {
kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
- ret = clear_user((void __user *) maddr, disp);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr, disp))
+ return -EFAULT;
maddr += disp;
}
@@ -1164,19 +1162,17 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
if (prot & PROT_WRITE && excess1 > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess1);
- ret = clear_user((void __user *) maddr + phdr->p_filesz,
- excess1);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr + phdr->p_filesz,
+ excess1))
+ return -EFAULT;
}
#else
if (excess > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess);
- ret = clear_user((void *) maddr + phdr->p_filesz, excess);
- if (ret)
- return ret;
+ if (clear_user((void *) maddr + phdr->p_filesz, excess))
+ return -EFAULT;
}
#endif
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling
2010-06-01 13:10 [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling David Howells
@ 2010-06-02 2:40 ` Takuya Yoshikawa
2010-06-02 8:20 ` Paul Mundt
1 sibling, 0 replies; 6+ messages in thread
From: Takuya Yoshikawa @ 2010-06-02 2:40 UTC (permalink / raw)
To: David Howells
Cc: torvalds, akpm, linux-kernel, Mike Frysinger, Alexander Viro,
Daisuke HATAYAMA, Paul Mundt
David Howells <dhowells@redhat.com> wrote:
> From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
>
Thanks for updating, improving, the explanation!
Takuya
> clear_user() returns the number of bytes that could not be copied rather than
> an error code. So we should return -EFAULT rather than directly returning the
> results.
>
> Without this patch, positive values may be returned to elf_fdpic_map_file()
> and the following error handlings do not function as expected.
>
> 1.
> ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
> if (ret < 0)
> return ret;
> 2.
> ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
> if (ret < 0)
> return ret;
>
> Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Acked-by: Mike Frysinger <vapier@gentoo.org>
> CC: Alexander Viro <viro@zeniv.linux.org.uk>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
> CC: Paul Mundt <lethal@linux-sh.org>
> ---
>
> fs/binfmt_elf_fdpic.c | 26 +++++++++++---------------
> 1 files changed, 11 insertions(+), 15 deletions(-)
>
>
> diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
> index 2c5f9a0..63039ed 100644
> --- a/fs/binfmt_elf_fdpic.c
> +++ b/fs/binfmt_elf_fdpic.c
> @@ -990,10 +990,9 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
>
> /* clear any space allocated but not loaded */
> if (phdr->p_filesz < phdr->p_memsz) {
> - ret = clear_user((void *) (seg->addr + phdr->p_filesz),
> - phdr->p_memsz - phdr->p_filesz);
> - if (ret)
> - return ret;
> + if (clear_user((void *) (seg->addr + phdr->p_filesz),
> + phdr->p_memsz - phdr->p_filesz))
> + return -EFAULT;
> }
>
> if (mm) {
> @@ -1027,7 +1026,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
> struct elf32_fdpic_loadseg *seg;
> struct elf32_phdr *phdr;
> unsigned long load_addr, delta_vaddr;
> - int loop, dvset, ret;
> + int loop, dvset;
>
> load_addr = params->load_addr;
> delta_vaddr = 0;
> @@ -1127,9 +1126,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
> * PT_LOAD */
> if (prot & PROT_WRITE && disp > 0) {
> kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
> - ret = clear_user((void __user *) maddr, disp);
> - if (ret)
> - return ret;
> + if (clear_user((void __user *) maddr, disp))
> + return -EFAULT;
> maddr += disp;
> }
>
> @@ -1164,19 +1162,17 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
> if (prot & PROT_WRITE && excess1 > 0) {
> kdebug("clear[%d] ad=%lx sz=%lx",
> loop, maddr + phdr->p_filesz, excess1);
> - ret = clear_user((void __user *) maddr + phdr->p_filesz,
> - excess1);
> - if (ret)
> - return ret;
> + if (clear_user((void __user *) maddr + phdr->p_filesz,
> + excess1))
> + return -EFAULT;
> }
>
> #else
> if (excess > 0) {
> kdebug("clear[%d] ad=%lx sz=%lx",
> loop, maddr + phdr->p_filesz, excess);
> - ret = clear_user((void *) maddr + phdr->p_filesz, excess);
> - if (ret)
> - return ret;
> + if (clear_user((void *) maddr + phdr->p_filesz, excess))
> + return -EFAULT;
> }
> #endif
>
>
--
Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling
2010-06-01 13:10 [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling David Howells
2010-06-02 2:40 ` Takuya Yoshikawa
@ 2010-06-02 8:20 ` Paul Mundt
1 sibling, 0 replies; 6+ messages in thread
From: Paul Mundt @ 2010-06-02 8:20 UTC (permalink / raw)
To: David Howells
Cc: torvalds, akpm, linux-kernel, Takuya Yoshikawa, Mike Frysinger,
Alexander Viro, Daisuke HATAYAMA
On Tue, Jun 01, 2010 at 02:10:47PM +0100, David Howells wrote:
> From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
>
> clear_user() returns the number of bytes that could not be copied rather than
> an error code. So we should return -EFAULT rather than directly returning the
> results.
>
> Without this patch, positive values may be returned to elf_fdpic_map_file()
> and the following error handlings do not function as expected.
>
> 1.
> ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
> if (ret < 0)
> return ret;
> 2.
> ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
> if (ret < 0)
> return ret;
>
> Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Acked-by: Mike Frysinger <vapier@gentoo.org>
> CC: Alexander Viro <viro@zeniv.linux.org.uk>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
> CC: Paul Mundt <lethal@linux-sh.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] binfmt_elf_fdpic: fix clear_user() error handling
@ 2010-05-28 7:56 Takuya Yoshikawa
2010-05-28 17:38 ` Mike Frysinger
0 siblings, 1 reply; 6+ messages in thread
From: Takuya Yoshikawa @ 2010-05-28 7:56 UTC (permalink / raw)
To: akpm, viro
Cc: d.hatayama, dhowells, vapier, lethal, takuya.yoshikawa,
linux-fsdevel, linux-kernel
Hi, I found some places in bin_elf_fdpic at which clear_user() is
incorrectly handled, by chance, when I was trying to check how to
use clear_user().
IIUC, the following commit was not correct.
commit ab4ad55512e95b68ca3e25516068e18874f89252
bin_elf_fdpic: check the return value of clear_user
Although I don't have an appropriate test box for this, I wrote a
simple patch to fix this. So if this is worth fixing, please pick
this up.
Thanks,
Takuya
===
clear_user() returns the number of bytes, unsigned long, that could not
be copied. So we should return -EFAULT rather than directly return the results.
Without this patch, positive values may be passed to elf_fdpic_map_file() and
the following error handlings do not function as expected.
1.
ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
if (ret < 0)
return ret;
2.
ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
if (ret < 0)
return ret;
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
CC: David Howells <dhowells@redhat.com>
CC: Mike Frysinger <vapier@gentoo.org>
CC: Paul Mundt <lethal@linux-sh.org>
---
fs/binfmt_elf_fdpic.c | 26 +++++++++++---------------
1 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 2c5f9a0..63039ed 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -990,10 +990,9 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(
/* clear any space allocated but not loaded */
if (phdr->p_filesz < phdr->p_memsz) {
- ret = clear_user((void *) (seg->addr + phdr->p_filesz),
- phdr->p_memsz - phdr->p_filesz);
- if (ret)
- return ret;
+ if (clear_user((void *) (seg->addr + phdr->p_filesz),
+ phdr->p_memsz - phdr->p_filesz))
+ return -EFAULT;
}
if (mm) {
@@ -1027,7 +1026,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
struct elf32_fdpic_loadseg *seg;
struct elf32_phdr *phdr;
unsigned long load_addr, delta_vaddr;
- int loop, dvset, ret;
+ int loop, dvset;
load_addr = params->load_addr;
delta_vaddr = 0;
@@ -1127,9 +1126,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
* PT_LOAD */
if (prot & PROT_WRITE && disp > 0) {
kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
- ret = clear_user((void __user *) maddr, disp);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr, disp))
+ return -EFAULT;
maddr += disp;
}
@@ -1164,19 +1162,17 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
if (prot & PROT_WRITE && excess1 > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess1);
- ret = clear_user((void __user *) maddr + phdr->p_filesz,
- excess1);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr + phdr->p_filesz,
+ excess1))
+ return -EFAULT;
}
#else
if (excess > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess);
- ret = clear_user((void *) maddr + phdr->p_filesz, excess);
- if (ret)
- return ret;
+ if (clear_user((void *) maddr + phdr->p_filesz, excess))
+ return -EFAULT;
}
#endif
--
1.7.0.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] binfmt_elf_fdpic: fix clear_user() error handling
2010-05-28 7:56 [PATCH] binfmt_elf_fdpic: fix " Takuya Yoshikawa
@ 2010-05-28 17:38 ` Mike Frysinger
2010-06-01 12:29 ` David Howells
0 siblings, 1 reply; 6+ messages in thread
From: Mike Frysinger @ 2010-05-28 17:38 UTC (permalink / raw)
To: Takuya Yoshikawa
Cc: akpm, viro, d.hatayama, dhowells, lethal, takuya.yoshikawa,
linux-fsdevel, linux-kernel
On Fri, May 28, 2010 at 03:56, Takuya Yoshikawa wrote:
> Hi, I found some places in bin_elf_fdpic at which clear_user() is
> incorrectly handled, by chance, when I was trying to check how to
> use clear_user().
>
> IIUC, the following commit was not correct.
>
> commit ab4ad55512e95b68ca3e25516068e18874f89252
> bin_elf_fdpic: check the return value of clear_user
>
> Although I don't have an appropriate test box for this, I wrote a
> simple patch to fix this. So if this is worth fixing, please pick
> this up.
the intention was that these functions return 0 only on success, and
non-zero otherwise. along those lines, the patch does what was
intended. unfortunately, the logic calling these funcs only checks
for negative values.
> clear_user() returns the number of bytes, unsigned long, that could not
> be copied. So we should return -EFAULT rather than directly return the results.
>
> Without this patch, positive values may be passed to elf_fdpic_map_file() and
> the following error handlings do not function as expected.
on nommu systems, this is generally not an issue because clear_user()
is basically a memset(). but it's good to handle every case.
Acked-by: Mike Frysinger <vapier@gentoo.org>
-mike
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] binfmt_elf_fdpic: fix clear_user() error handling
2010-05-28 17:38 ` Mike Frysinger
@ 2010-06-01 12:29 ` David Howells
0 siblings, 0 replies; 6+ messages in thread
From: David Howells @ 2010-06-01 12:29 UTC (permalink / raw)
To: Mike Frysinger
Cc: dhowells, Takuya Yoshikawa, akpm, viro, d.hatayama, lethal,
takuya.yoshikawa, linux-fsdevel, linux-kernel
Mike Frysinger <vapier.adi@gmail.com> wrote:
> on nommu systems, this is generally not an issue because clear_user()
> is basically a memset(). but it's good to handle every case.
But FDPIC is used on MMU systems too.
David
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-06-02 8:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2010-06-01 13:10 [PATCH] binfmt_elf_fdpic: Fix clear_user() error handling David Howells
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