diff options
| author | Dan Rosenberg <drosenberg@vsecurity.com> | 2011-03-19 20:43:43 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-03-27 17:59:03 -0700 |
| commit | be20250c13f88375345ad99950190685eda51eb8 (patch) | |
| tree | 71135bced4717604dff6e37d00f06f20870bbe1c /net/rose | |
| parent | d370af0ef7951188daeb15bae75db7ba57c67846 (diff) | |
| download | lwn-be20250c13f88375345ad99950190685eda51eb8.tar.gz lwn-be20250c13f88375345ad99950190685eda51eb8.zip | |
ROSE: prevent heap corruption with bad facilities
When parsing the FAC_NATIONAL_DIGIS facilities field, it's possible for
a remote host to provide more digipeaters than expected, resulting in
heap corruption. Check against ROSE_MAX_DIGIS to prevent overflows, and
abort facilities parsing on failure.
Additionally, when parsing the FAC_CCITT_DEST_NSAP and
FAC_CCITT_SRC_NSAP facilities fields, a remote host can provide a length
of less than 10, resulting in an underflow in a memcpy size, causing a
kernel panic due to massive heap corruption. A length of greater than
20 results in a stack overflow of the callsign array. Abort facilities
parsing on these invalid length values.
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rose')
| -rw-r--r-- | net/rose/rose_subr.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/net/rose/rose_subr.c b/net/rose/rose_subr.c index 1734abba26a2..174d51c9ce37 100644 --- a/net/rose/rose_subr.c +++ b/net/rose/rose_subr.c @@ -290,10 +290,15 @@ static int rose_parse_national(unsigned char *p, struct rose_facilities_struct * facilities->source_ndigis = 0; facilities->dest_ndigis = 0; for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) { - if (pt[6] & AX25_HBIT) + if (pt[6] & AX25_HBIT) { + if (facilities->dest_ndigis >= ROSE_MAX_DIGIS) + return -1; memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN); - else + } else { + if (facilities->source_ndigis >= ROSE_MAX_DIGIS) + return -1; memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN); + } } } p += l + 2; @@ -333,6 +338,11 @@ static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *fac case 0xC0: l = p[1]; + + /* Prevent overflows*/ + if (l < 10 || l > 20) + return -1; + if (*p == FAC_CCITT_DEST_NSAP) { memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN); memcpy(callsign, p + 12, l - 10); @@ -373,12 +383,16 @@ int rose_parse_facilities(unsigned char *p, switch (*p) { case FAC_NATIONAL: /* National */ len = rose_parse_national(p + 1, facilities, facilities_len - 1); + if (len < 0) + return 0; facilities_len -= len + 1; p += len + 1; break; case FAC_CCITT: /* CCITT */ len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1); + if (len < 0) + return 0; facilities_len -= len + 1; p += len + 1; break; |