| Patrick Williams | 821a859 | 2023-05-02 15:26:54 -0500 | [diff] [blame^] | 1 | From a15f7d9913d050fb72a79bbbefa5c2329d92e71d Mon Sep 17 00:00:00 2001 |
| 2 | From: Hitendra Prajapati <hprajapati@mvista.com> |
| 3 | Date: Tue, 8 Nov 2022 17:10:00 +0530 |
| 4 | Subject: [PATCH] CVE-2022-3165 |
| 5 | |
| 6 | Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/d307040b18] |
| 7 | CVE: CVE-2022-3165 |
| 8 | Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com> |
| 9 | |
| 10 | ui/vnc-clipboard: fix integer underflow in vnc_client_cut_text_ext |
| 11 | |
| 12 | Extended ClientCutText messages start with a 4-byte header. If len < 4, |
| 13 | an integer underflow occurs in vnc_client_cut_text_ext. The result is |
| 14 | used to decompress data in a while loop in inflate_buffer, leading to |
| 15 | CPU consumption and denial of service. Prevent this by checking dlen in |
| 16 | protocol_client_msg. |
| 17 | |
| 18 | Fixes: CVE-2022-3165 |
| 19 | |
| 20 | ("ui/vnc: clipboard support") |
| 21 | Reported-by: default avatarTangPeng <tangpeng@qianxin.com> |
| 22 | Signed-off-by: Mauro Matteo Cascella's avatarMauro Matteo Cascella <mcascell@redhat.com> |
| 23 | Message-Id: <20220925204511.1103214-1-mcascell@redhat.com> |
| 24 | Signed-off-by: Gerd Hoffmann's avatarGerd Hoffmann <kraxel@redhat.com> |
| 25 | --- |
| 26 | ui/vnc.c | 11 ++++++++--- |
| 27 | 1 file changed, 8 insertions(+), 3 deletions(-) |
| 28 | |
| 29 | diff --git a/ui/vnc.c b/ui/vnc.c |
| 30 | index af02522e8..a14b6861b 100644 |
| 31 | --- a/ui/vnc.c |
| 32 | +++ b/ui/vnc.c |
| 33 | @@ -2442,8 +2442,8 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len) |
| 34 | if (len == 1) { |
| 35 | return 8; |
| 36 | } |
| 37 | + uint32_t dlen = abs(read_s32(data, 4)); |
| 38 | if (len == 8) { |
| 39 | - uint32_t dlen = abs(read_s32(data, 4)); |
| 40 | if (dlen > (1 << 20)) { |
| 41 | error_report("vnc: client_cut_text msg payload has %u bytes" |
| 42 | " which exceeds our limit of 1MB.", dlen); |
| 43 | @@ -2456,8 +2456,13 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len) |
| 44 | } |
| 45 | |
| 46 | if (read_s32(data, 4) < 0) { |
| 47 | - vnc_client_cut_text_ext(vs, abs(read_s32(data, 4)), |
| 48 | - read_u32(data, 8), data + 12); |
| 49 | + if (dlen < 4) { |
| 50 | + error_report("vnc: malformed payload (header less than 4 bytes)" |
| 51 | + " in extended clipboard pseudo-encoding."); |
| 52 | + vnc_client_error(vs); |
| 53 | + break; |
| 54 | + } |
| 55 | + vnc_client_cut_text_ext(vs, dlen, read_u32(data, 8), data + 12); |
| 56 | break; |
| 57 | } |
| 58 | vnc_client_cut_text(vs, read_u32(data, 4), data + 8); |
| 59 | -- |
| 60 | 2.25.1 |
| 61 | |