diff options
author | Chris Wright <chrisw@sous-sol.org> | 2008-06-04 09:16:33 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-06-05 14:24:54 -0700 |
commit | ddb2c43594f22843e9f3153da151deaba1a834c5 (patch) | |
tree | 7eeeca2fa55e9ef45c381b01d9e3ec1b726297c1 /fs/cifs/asn1.c | |
parent | efedf51c866130945b5db755cb58670e60205d83 (diff) | |
download | linux-ddb2c43594f22843e9f3153da151deaba1a834c5.tar.bz2 |
asn1: additional sanity checking during BER decoding
- 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 'fs/cifs/asn1.c')
-rw-r--r-- | fs/cifs/asn1.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c index cb52cbbe45ff..f58e41d3ba48 100644 --- a/fs/cifs/asn1.c +++ b/fs/cifs/asn1.c @@ -186,6 +186,11 @@ asn1_length_decode(struct asn1_ctx *ctx, unsigned int *def, unsigned int *len) } } } + + /* don't trust len bigger than ctx buffer */ + if (*len > ctx->end - ctx->pointer) + return 0; + return 1; } @@ -203,6 +208,10 @@ 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 @@ -389,6 +398,11 @@ 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) return 0; |