Messages in this thread Patch in this message | | | Date | Mon, 7 Sep 2015 20:11:48 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH] zram: fix possible use after free in zcomp_create() |
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On (09/07/15 11:33), Luis Henriques wrote: > zcomp_create() verifies the success of zcomp_strm_{multi,siggle}_create() > through comp->stream, which can potentially be pointing to memory that was > freed if these functions returned an error. >
good catch.
we probably better start checking the zcomp_strm_multi_create()/ zcomp_strm_single_create() status in zcomp_create(); that's much more obvious and that's why we return it in the first place.
what do you think?
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drivers/block/zram/zcomp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 3456d5a..16bbc8c 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -360,6 +360,7 @@ struct zcomp *zcomp_create(const char *compress, int max_strm) { struct zcomp *comp; struct zcomp_backend *backend; + int ret; backend = find_backend(compress); if (!backend) @@ -371,10 +372,10 @@ struct zcomp *zcomp_create(const char *compress, int max_strm) comp->backend = backend; if (max_strm > 1) - zcomp_strm_multi_create(comp, max_strm); + ret = zcomp_strm_multi_create(comp, max_strm); else - zcomp_strm_single_create(comp); - if (!comp->stream) { + ret = zcomp_strm_single_create(comp); + if (ret != 0) { kfree(comp); return ERR_PTR(-ENOMEM); }
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