francis.wang
4c86c082a2
Combine poky (Yocto scarthgap), meta-openembedded (scarthgap), and meta-openwrt into a single repository. Components: - poky/ Yocto core framework (BitBake + OE-Core) - meta-openembedded/ Community layers (meta-oe, meta-python, meta-networking) - meta-openwrt/ OpenWrt customization layer - setup-env.sh One-click build environment setup - README.md Project documentation
42 lines
1.6 KiB
Diff
42 lines
1.6 KiB
Diff
From 2f029069825270a3b91eb5f50bb8477ed7f761d3 Mon Sep 17 00:00:00 2001
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From: Simon Kelley <simon@thekelleys.org.uk>
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Date: Wed, 25 Mar 2026 23:16:35 +0000
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Subject: [PATCH] Fix buffer overflow in helper.c with large CLIDs.
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CVE-2026-4892
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Bug reported bt Royce M <royce@xchglabs.com>
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Location: helper.c:265-270
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DHCPv6 CLIDs can be up to 65535 bytes. When --dhcp-script is configured,
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the helper hex-encodes raw CLID bytes via sprintf("%.2x") into daemon->packet (5131 bytes).
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A 1000-byte CLID writes ~3000 bytes. The helper process retains root privileges.
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Note: log6_packet() correctly caps CLID to 100 bytes for logging, but the helper code path was missed.
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CVE: CVE-2026-4892
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Upstream-Status: Backport [https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=10e6b5b83e80749cba7b090d7780b29f908f0571]
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Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
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---
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src/helper.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/src/helper.c b/src/helper.c
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index b9da2259..3a31e618 100644
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--- a/src/helper.c
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+++ b/src/helper.c
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@@ -261,8 +261,8 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
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data.hostname_len + data.ed_len + data.clid_len, 1))
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continue;
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- /* CLID into packet */
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- for (p = daemon->packet, i = 0; i < data.clid_len; i++)
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+ /* CLID into packet: limit to 100 bytes to avoid overflowing buffer. */
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+ for (p = daemon->packet, i = 0; i < data.clid_len && i < 100; i++)
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{
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p += sprintf(p, "%.2x", buf[i]);
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if (i != data.clid_len - 1)
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--
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2.43.0
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