diff options
| author | Chris Wright <chrisw@sous-sol.org> | 2008-06-04 09:16:33 -0700 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2008-06-06 16:04:46 -0700 |
| commit | 33afb8403f361919aa5c8fe1d0a4f5ddbfbbea3c (patch) | |
| tree | 2b95d72be1b19dbb8d3963f8bd9a798652831668 /net/ipv4 | |
| parent | a82a9bfebc74862798a3f6949fe6f6a959c1fd4e (diff) | |
asn1: additional sanity checking during BER decoding (CVE-2008-1673)
upstream commit: ddb2c43594f22843e9f3153da151deaba1a834c5
- Don't trust a length which is greater than the working buffer.
An invalid length could cause overflow when calculating buffer size
for decoding oid.
- An oid length of zero is invalid and allows for an off-by-one error when
decoding oid because the first subid actually encodes first 2 subids.
- A primitive encoding may not have an indefinite length.
Thanks to Wei Wang from McAfee for report.
Cc: Steven French <sfrench@us.ibm.com>
Cc: stable@kernel.org
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/netfilter/nf_nat_snmp_basic.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nf_nat_snmp_basic.c b/net/ipv4/netfilter/nf_nat_snmp_basic.c index 540ce6ae887c..5f35f0b589db 100644 --- a/net/ipv4/netfilter/nf_nat_snmp_basic.c +++ b/net/ipv4/netfilter/nf_nat_snmp_basic.c @@ -231,6 +231,11 @@ static unsigned char asn1_length_decode(struct asn1_ctx *ctx, } } } + + /* don't trust len bigger than ctx buffer */ + if (*len > ctx->end - ctx->pointer) + return 0; + return 1; } @@ -249,6 +254,10 @@ static unsigned char asn1_header_decode(struct asn1_ctx *ctx, if (!asn1_length_decode(ctx, &def, &len)) return 0; + /* primitive shall be definite, indefinite shall be constructed */ + if (*con == ASN1_PRI && !def) + return 0; + if (def) *eoc = ctx->pointer + len; else @@ -433,6 +442,11 @@ static unsigned char asn1_oid_decode(struct asn1_ctx *ctx, unsigned long *optr; size = eoc - ctx->pointer + 1; + + /* first subid actually encodes first two subids */ + if (size < 2 || size > ULONG_MAX/sizeof(unsigned long)) + return 0; + *oid = kmalloc(size * sizeof(unsigned long), GFP_ATOMIC); if (*oid == NULL) { if (net_ratelimit()) |