* [PATCH] Btrfs: fix null pointer dereference on compressed write path error
@ 2018-10-12 20:45 fdmanana
2018-10-12 23:37 ` [PATCH v2] " fdmanana
0 siblings, 1 reply; 4+ messages in thread
From: fdmanana @ 2018-10-12 20:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
At inode.c:compress_file_range(), under the "free_pages_out" label, we can
end up dereferencing the "pages" pointer when it has a NULL value. This
case happens when "start" has a value of 0 and we fail to allocate memory
for the "pages" pointer. When that happens we jump to the "cont" label and
then enter the "if (start == 0)" branch where we immediately call the
cow_file_range_inline() function. If that function returns an error (like
-ENOMEM for example) we jump to the "free_pages_out" label and then access
"pages[i]" leading to a NULL pointer dereference, since "nr_pages" has a
value greater than zero at that point.
Fix this by setting "nr_pages" to 0 when we fail to allocate memory for
the "pages" pointer.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201119
Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/inode.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 66c6c4103d2f..d6b61b1facdd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -503,6 +503,7 @@ static noinline void compress_file_range(struct inode *inode,
pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
if (!pages) {
/* just bail out to the uncompressed code */
+ nr_pages = 0;
goto cont;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2] Btrfs: fix null pointer dereference on compressed write path error
2018-10-12 20:45 [PATCH] Btrfs: fix null pointer dereference on compressed write path error fdmanana
@ 2018-10-12 23:37 ` fdmanana
2018-10-13 0:56 ` Liu Bo
2018-10-16 9:32 ` David Sterba
0 siblings, 2 replies; 4+ messages in thread
From: fdmanana @ 2018-10-12 23:37 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
At inode.c:compress_file_range(), under the "free_pages_out" label, we can
end up dereferencing the "pages" pointer when it has a NULL value. This
case happens when "start" has a value of 0 and we fail to allocate memory
for the "pages" pointer. When that happens we jump to the "cont" label and
then enter the "if (start == 0)" branch where we immediately call the
cow_file_range_inline() function. If that function returns 0 (success
creating an inline extent) or an error (like -ENOMEM for example) we jump
to the "free_pages_out" label and then access "pages[i]" leading to a NULL
pointer dereference, since "nr_pages" has a value greater than zero at
that point.
Fix this by setting "nr_pages" to 0 when we fail to allocate memory for
the "pages" pointer.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201119
Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
V2: Updated changelog.
fs/btrfs/inode.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 66c6c4103d2f..d6b61b1facdd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -503,6 +503,7 @@ static noinline void compress_file_range(struct inode *inode,
pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
if (!pages) {
/* just bail out to the uncompressed code */
+ nr_pages = 0;
goto cont;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] Btrfs: fix null pointer dereference on compressed write path error
2018-10-12 23:37 ` [PATCH v2] " fdmanana
@ 2018-10-13 0:56 ` Liu Bo
2018-10-16 9:32 ` David Sterba
1 sibling, 0 replies; 4+ messages in thread
From: Liu Bo @ 2018-10-13 0:56 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
On Fri, Oct 12, 2018 at 4:38 PM <fdmanana@kernel.org> wrote:
>
> From: Filipe Manana <fdmanana@suse.com>
>
> At inode.c:compress_file_range(), under the "free_pages_out" label, we can
> end up dereferencing the "pages" pointer when it has a NULL value. This
> case happens when "start" has a value of 0 and we fail to allocate memory
> for the "pages" pointer. When that happens we jump to the "cont" label and
> then enter the "if (start == 0)" branch where we immediately call the
> cow_file_range_inline() function. If that function returns 0 (success
> creating an inline extent) or an error (like -ENOMEM for example) we jump
> to the "free_pages_out" label and then access "pages[i]" leading to a NULL
> pointer dereference, since "nr_pages" has a value greater than zero at
> that point.
>
> Fix this by setting "nr_pages" to 0 when we fail to allocate memory for
> the "pages" pointer.
>
Looks good.
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
thanks,
liubo
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201119
> Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
>
> V2: Updated changelog.
>
> fs/btrfs/inode.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 66c6c4103d2f..d6b61b1facdd 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -503,6 +503,7 @@ static noinline void compress_file_range(struct inode *inode,
> pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
> if (!pages) {
> /* just bail out to the uncompressed code */
> + nr_pages = 0;
> goto cont;
> }
>
> --
> 2.11.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] Btrfs: fix null pointer dereference on compressed write path error
2018-10-12 23:37 ` [PATCH v2] " fdmanana
2018-10-13 0:56 ` Liu Bo
@ 2018-10-16 9:32 ` David Sterba
1 sibling, 0 replies; 4+ messages in thread
From: David Sterba @ 2018-10-16 9:32 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
On Sat, Oct 13, 2018 at 12:37:25AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> At inode.c:compress_file_range(), under the "free_pages_out" label, we can
> end up dereferencing the "pages" pointer when it has a NULL value. This
> case happens when "start" has a value of 0 and we fail to allocate memory
> for the "pages" pointer. When that happens we jump to the "cont" label and
> then enter the "if (start == 0)" branch where we immediately call the
> cow_file_range_inline() function. If that function returns 0 (success
> creating an inline extent) or an error (like -ENOMEM for example) we jump
> to the "free_pages_out" label and then access "pages[i]" leading to a NULL
> pointer dereference, since "nr_pages" has a value greater than zero at
> that point.
>
> Fix this by setting "nr_pages" to 0 when we fail to allocate memory for
> the "pages" pointer.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201119
> Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
Added to misc-next, thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-10-16 9:33 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-12 20:45 [PATCH] Btrfs: fix null pointer dereference on compressed write path error fdmanana
2018-10-12 23:37 ` [PATCH v2] " fdmanana
2018-10-13 0:56 ` Liu Bo
2018-10-16 9:32 ` David Sterba
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.