CVE-2011-1493 (published 2012-06-21T23:55Z)

Array index error in the rose_parse_national function in net/rose/rose_subr.c in the Linux kernel before 2.6.39 allows remote attackers to cause a denial of service (heap memory corruption) or possibly have unspecified other impact by composing FAC_NATIONAL_DIGIS data that specifies a large number of digipeaters, and then sending this data to a ROSE socket.

Severity: HIGH
CVSS v2 base score: 7.5 (AV:N/AC:L/Au:N/C:P/I:P/A:P)

Weakness information:
cwe_id: NVD-CWE-Other
cwe_name: Other
description: NVD is only using a subset of CWE for mapping instead of the entire CWE, and the weakness type is not covered by that subset.
extended_description: Insufficient Information

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Dan Rosenberg
author_date: 2011-03-19 20:43:43+00:00
msg: 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>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: rose_subr.c
change_type: ModificationType.MODIFY
diff: @@ -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;

programming_language: C