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>
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1 changed files with 16 additions and 2 deletions
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@ -290,10 +290,15 @@ static int rose_parse_national(unsigned char *p, struct rose_facilities_struct *
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facilities->source_ndigis = 0;
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facilities->dest_ndigis = 0;
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for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) {
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if (pt[6] & AX25_HBIT)
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if (pt[6] & AX25_HBIT) {
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if (facilities->dest_ndigis >= ROSE_MAX_DIGIS)
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return -1;
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memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN);
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else
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} else {
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if (facilities->source_ndigis >= ROSE_MAX_DIGIS)
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return -1;
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memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN);
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}
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}
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}
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p += l + 2;
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@ -333,6 +338,11 @@ static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *fac
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case 0xC0:
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l = p[1];
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/* Prevent overflows*/
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if (l < 10 || l > 20)
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return -1;
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if (*p == FAC_CCITT_DEST_NSAP) {
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memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN);
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memcpy(callsign, p + 12, l - 10);
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@ -373,12 +383,16 @@ int rose_parse_facilities(unsigned char *p,
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switch (*p) {
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case FAC_NATIONAL: /* National */
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len = rose_parse_national(p + 1, facilities, facilities_len - 1);
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if (len < 0)
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return 0;
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facilities_len -= len + 1;
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p += len + 1;
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break;
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case FAC_CCITT: /* CCITT */
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len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1);
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if (len < 0)
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return 0;
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facilities_len -= len + 1;
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p += len + 1;
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break;
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