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authorHerbert Xu <herbert@gondor.apana.org.au>2019-06-24 10:32:26 (GMT)
committerHerbert Xu <herbert@gondor.apana.org.au>2019-07-03 14:11:55 (GMT)
commitc8ea9fce2baf7b643384f36f29e4194fa40d33a6 (patch)
treeac6c28eff7d957212a01d18d2dc932ef9b54b3a6 /lib
parent7829a0c1cb9c80debfb4fdb49b4d90019f2ea1ac (diff)
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lib/mpi: Fix karactx leak in mpi_powm
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...") Cc: <stable@vger.kernel.org> 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>
Diffstat (limited to 'lib')
-rw-r--r--lib/mpi/mpi-pow.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/lib/mpi/mpi-pow.c b/lib/mpi/mpi-pow.c
index a5c921e..d3ca550 100644
--- a/lib/mpi/mpi-pow.c
+++ b/lib/mpi/mpi-pow.c
@@ -37,6 +37,7 @@
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;
@@ -294,8 +293,6 @@ 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) {
@@ -312,6 +309,7 @@ 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)