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authorLuis Henriques <luis.henriques@canonical.com>2015-09-17 16:01:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-17 21:16:07 -0700
commit3aaf14da807a4e9931a37f21e4251abb8a67021b (patch)
treec51131105c74598a587d4bfddc7b4b4d2df5bbb4
parent72714841b705a5b9bccf37ee85a62352bee3a3ef (diff)
downloadlinux-sh-3aaf14da807a4e9931a37f21e4251abb8a67021b.tar.gz
zram: fix possible use after free in zcomp_create()
zcomp_create() verifies the success of zcomp_strm_{multi,single}_create() through comp->stream, which can potentially be pointing to memory that was freed if these functions returned an error. While at it, replace a 'ERR_PTR(-ENOMEM)' by a more generic 'ERR_PTR(error)' as in the future zcomp_strm_{multi,siggle}_create() could return other error codes. Function documentation updated accordingly. Fixes: beca3ec71fe5 ("zram: add multi stream functionality") Signed-off-by: Luis Henriques <luis.henriques@canonical.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/block/zram/zcomp.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 965d1afb0eaa..5cb13ca3a3ac 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -330,12 +330,14 @@ void zcomp_destroy(struct zcomp *comp)
* allocate new zcomp and initialize it. return compressing
* backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
* if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
- * case of allocation error.
+ * case of allocation error, or any other error potentially
+ * returned by functions zcomp_strm_{multi,single}_create.
*/
struct zcomp *zcomp_create(const char *compress, int max_strm)
{
struct zcomp *comp;
struct zcomp_backend *backend;
+ int error;
backend = find_backend(compress);
if (!backend)
@@ -347,12 +349,12 @@ struct zcomp *zcomp_create(const char *compress, int max_strm)
comp->backend = backend;
if (max_strm > 1)
- zcomp_strm_multi_create(comp, max_strm);
+ error = zcomp_strm_multi_create(comp, max_strm);
else
- zcomp_strm_single_create(comp);
- if (!comp->stream) {
+ error = zcomp_strm_single_create(comp);
+ if (error) {
kfree(comp);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(error);
}
return comp;
}