| Patrick Williams | 2390b1b | 2022-11-03 13:47:49 -0500 | [diff] [blame] | 1 | CVE: CVE-2022-3165 |
| 2 | Upstream-Status: Backport |
| 3 | Signed-off-by: Ross Burton <ross.burton@arm.com> |
| 4 | |
| 5 | From d307040b18bfcb1393b910f1bae753d5c12a4dc7 Mon Sep 17 00:00:00 2001 |
| 6 | From: Mauro Matteo Cascella <mcascell@redhat.com> |
| 7 | Date: Sun, 25 Sep 2022 22:45:11 +0200 |
| 8 | Subject: [PATCH] ui/vnc-clipboard: fix integer underflow in |
| 9 | vnc_client_cut_text_ext |
| 10 | |
| 11 | Extended ClientCutText messages start with a 4-byte header. If len < 4, |
| 12 | an integer underflow occurs in vnc_client_cut_text_ext. The result is |
| 13 | used to decompress data in a while loop in inflate_buffer, leading to |
| 14 | CPU consumption and denial of service. Prevent this by checking dlen in |
| 15 | protocol_client_msg. |
| 16 | |
| 17 | Fixes: CVE-2022-3165 |
| 18 | Fixes: 0bf41cab93e5 ("ui/vnc: clipboard support") |
| 19 | Reported-by: TangPeng <tangpeng@qianxin.com> |
| 20 | Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com> |
| 21 | Message-Id: <20220925204511.1103214-1-mcascell@redhat.com> |
| 22 | Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> |
| 23 | --- |
| 24 | ui/vnc.c | 11 ++++++++--- |
| 25 | 1 file changed, 8 insertions(+), 3 deletions(-) |
| 26 | |
| 27 | diff --git a/ui/vnc.c b/ui/vnc.c |
| 28 | index 6a05d06147..acb3629cd8 100644 |
| 29 | --- a/ui/vnc.c |
| 30 | +++ b/ui/vnc.c |
| 31 | @@ -2442,8 +2442,8 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len) |
| 32 | if (len == 1) { |
| 33 | return 8; |
| 34 | } |
| 35 | + uint32_t dlen = abs(read_s32(data, 4)); |
| 36 | if (len == 8) { |
| 37 | - uint32_t dlen = abs(read_s32(data, 4)); |
| 38 | if (dlen > (1 << 20)) { |
| 39 | error_report("vnc: client_cut_text msg payload has %u bytes" |
| 40 | " which exceeds our limit of 1MB.", dlen); |
| 41 | @@ -2456,8 +2456,13 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len) |
| 42 | } |
| 43 | |
| 44 | if (read_s32(data, 4) < 0) { |
| 45 | - vnc_client_cut_text_ext(vs, abs(read_s32(data, 4)), |
| 46 | - read_u32(data, 8), data + 12); |
| 47 | + if (dlen < 4) { |
| 48 | + error_report("vnc: malformed payload (header less than 4 bytes)" |
| 49 | + " in extended clipboard pseudo-encoding."); |
| 50 | + vnc_client_error(vs); |
| 51 | + break; |
| 52 | + } |
| 53 | + vnc_client_cut_text_ext(vs, dlen, read_u32(data, 8), data + 12); |
| 54 | break; |
| 55 | } |
| 56 | vnc_client_cut_text(vs, read_u32(data, 4), data + 8); |
| 57 | -- |
| 58 | GitLab |
| 59 | |