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lib/mpi: Fix karactx leak in mpi_powm
commitc8ea9fce2b
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:cdec9cb516
("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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443449d4a1
commit
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1 changed files with 2 additions and 4 deletions
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@ -37,6 +37,7 @@
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int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
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int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
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{
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{
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mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
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mpi_ptr_t mp_marker = NULL, bp_marker = NULL, ep_marker = NULL;
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struct karatsuba_ctx karactx = {};
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mpi_ptr_t xp_marker = NULL;
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mpi_ptr_t xp_marker = NULL;
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mpi_ptr_t tspace = NULL;
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mpi_ptr_t tspace = NULL;
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mpi_ptr_t rp, ep, mp, bp;
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mpi_ptr_t rp, ep, mp, bp;
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@ -164,13 +165,11 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
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int c;
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int c;
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mpi_limb_t e;
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mpi_limb_t e;
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mpi_limb_t carry_limb;
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mpi_limb_t carry_limb;
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struct karatsuba_ctx karactx;
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xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
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xp = xp_marker = mpi_alloc_limb_space(2 * (msize + 1));
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if (!xp)
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if (!xp)
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goto enomem;
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goto enomem;
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memset(&karactx, 0, sizeof karactx);
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negative_result = (ep[0] & 1) && base->sign;
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negative_result = (ep[0] & 1) && base->sign;
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i = esize - 1;
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i = esize - 1;
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@ -295,8 +294,6 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
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if (mod_shift_cnt)
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if (mod_shift_cnt)
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mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
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mpihelp_rshift(rp, rp, rsize, mod_shift_cnt);
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MPN_NORMALIZE(rp, rsize);
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MPN_NORMALIZE(rp, rsize);
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mpihelp_release_karatsuba_ctx(&karactx);
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}
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}
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if (negative_result && rsize) {
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if (negative_result && rsize) {
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@ -313,6 +310,7 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod)
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leave:
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leave:
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rc = 0;
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rc = 0;
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enomem:
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enomem:
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mpihelp_release_karatsuba_ctx(&karactx);
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if (assign_rp)
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if (assign_rp)
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mpi_assign_limb_space(res, rp, size);
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mpi_assign_limb_space(res, rp, size);
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if (mp_marker)
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if (mp_marker)
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