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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2019-06-24 18:32:26 +0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-10-05 16:20:08 +0100 |
| commit | 6880e07374031d7a9bd08db0c304caa2d3a44ede (patch) | |
| tree | cdde8405b6af57e0586fe760fb41d0c4bc5844d4 /lib | |
| parent | b172516360f05543b65e7c04bd81d36c9eeacb75 (diff) | |
| download | linux-stable-6880e07374031d7a9bd08db0c304caa2d3a44ede.tar.gz linux-stable-6880e07374031d7a9bd08db0c304caa2d3a44ede.tar.bz2 linux-stable-6880e07374031d7a9bd08db0c304caa2d3a44ede.zip | |
lib/mpi: Fix karactx leak in mpi_powm
commit c8ea9fce2baf7b643384f36f29e4194fa40d33a6 upstream.
Sometimes mpi_powm will leak karactx because a memory allocation
failure causes a bail-out that skips the freeing of karactx. This
patch moves the freeing of karactx to the end of the function like
everything else so that it can't be skipped.
Reported-by: syzbot+f7baccc38dcc1e094e77@syzkaller.appspotmail.com
Fixes: cdec9cb5167a ("crypto: GnuPG based MPI lib - source files...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/mpi/mpi-pow.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/lib/mpi/mpi-pow.c b/lib/mpi/mpi-pow.c index e24388a863a7..dc26594984ef 100644 --- a/lib/mpi/mpi-pow.c +++ b/lib/mpi/mpi-pow.c @@ -36,6 +36,7 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) { mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL; + struct karatsuba_ctx karactx = {}; mpi_ptr_t xp_marker = NULL; mpi_ptr_t tspace = NULL; mpi_ptr_t rp, ep, mp, bp; @@ -163,13 +164,11 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) int c; mpi_limb_t e; mpi_limb_t carry_limb; - struct karatsuba_ctx karactx; xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1)); if (!xp) goto enomem; - memset(&karactx, 0, sizeof karactx); negative_result = (ep[0] & 1) && base->sign; i = esize - 1; @@ -293,8 +292,6 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) if (mod_shift_cnt) mpihelp_rshift(rp, rp, rsize, mod_shift_cnt); MPN_NORMALIZE(rp, rsize); - - mpihelp_release_karatsuba_ctx(&karactx); } if (negative_result && rsize) { @@ -311,6 +308,7 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) leave: rc = 0; enomem: + mpihelp_release_karatsuba_ctx(&karactx); if (assign_rp) mpi_assign_limb_space(res, rp, size); if (mp_marker) |