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| author | Luis Henriques <luis.henriques@canonical.com> | 2015-09-17 16:01:40 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-03 13:51:39 +0200 |
| commit | 6abf903c8eb352a3705353789ac200d188466f16 (patch) | |
| tree | 9cd80e75e8e4d3888cfc99907a668d0b57f3ade0 | |
| parent | 92b52680751f95fa275c5a2dfb274de5c320d358 (diff) | |
| download | lwn-6abf903c8eb352a3705353789ac200d188466f16.tar.gz lwn-6abf903c8eb352a3705353789ac200d188466f16.zip | |
zram: fix possible use after free in zcomp_create()
commit 3aaf14da807a4e9931a37f21e4251abb8a67021b upstream.
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/block/zram/zcomp.c | 12 |
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; } |