From: Pi-Hsun Shih pihsun@chromium.org
commit a9fb94a99bb515d8720ba8440ce3aba84aec80f8 upstream.
Set tfm to NULL on free_buf_for_compression() after crypto_free_comp().
This avoid a use-after-free when allocate_buf_for_compression() and free_buf_for_compression() are called twice. Although free_buf_for_compression() freed the tfm, allocate_buf_for_compression() won't reinitialize the tfm since the tfm pointer is not NULL.
Fixes: 95047b0519c1 ("pstore: Refactor compression initialization") Signed-off-by: Pi-Hsun Shih pihsun@chromium.org Cc: stable@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/pstore/platform.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -347,8 +347,10 @@ static void allocate_buf_for_compression
static void free_buf_for_compression(void) { - if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) + if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) { crypto_free_comp(tfm); + tfm = NULL; + } kfree(big_oops_buf); big_oops_buf = NULL; big_oops_buf_sz = 0;