diff mbox series

[scarthgap,3/4] gawk: Fix CVE-2026-40469

Message ID 20260722095627.1424705-3-dkelaiya@cisco.com
State New
Headers show
Series [scarthgap,1/4] gawk: Fix CVE-2026-40467 | expand

Commit Message

From: Darsh Kelaiya <dkelaiya@cisco.com>

NVD [3] identifies upstream merge commit [2] as the fix. The
CVE-specific change is its second parent [1], which adds 32-bit
overflow checking in do_sub().

[1] https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=aa7272a6e1184cdd21ab8f89200219abd8053eda
[2] https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=ae1b2d508f46913269a9e62aceda3636afe8147b
[3] https://nvd.nist.gov/vuln/detail/CVE-2026-40469

Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
---
 .../gawk/gawk/CVE-2026-40469.patch            | 90 +++++++++++++++++++
 meta/recipes-extended/gawk/gawk_5.3.0.bb      |  1 +
 2 files changed, 91 insertions(+)
 create mode 100644 meta/recipes-extended/gawk/gawk/CVE-2026-40469.patch

Comments

Leonid Iziumtsev July 22, 2026, 12:36 p.m. UTC | #1
Looks good to me.

Reviewed-by: Leonid Iziumtsev <leonid.iziumtsev@est.tech>
diff mbox series

Patch

diff --git a/meta/recipes-extended/gawk/gawk/CVE-2026-40469.patch b/meta/recipes-extended/gawk/gawk/CVE-2026-40469.patch
new file mode 100644
index 0000000000..49b6a23b01
--- /dev/null
+++ b/meta/recipes-extended/gawk/gawk/CVE-2026-40469.patch
@@ -0,0 +1,90 @@ 
+From f907980a3e7a58006b796308021c8410a24e0f3c Mon Sep 17 00:00:00 2001
+From: "Arnold D. Robbins" <arnold@skeeve.com>
+Date: Mon, 6 Apr 2026 10:56:38 +0300
+Subject: [PATCH] Add overflow checking in do_sub for 32 bit systems.
+
+CVE: CVE-2026-40469
+Upstream-Status: Backport [https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=aa7272a6e1184cdd21ab8f89200219abd8053eda]
+
+(cherry picked from commit aa7272a6e1184cdd21ab8f89200219abd8053eda)
+Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
+---
+ ChangeLog |  9 +++++++++
+ builtin.c | 25 ++++++++++++++++++++-----
+ 2 files changed, 29 insertions(+), 5 deletions(-)
+
+diff --git a/ChangeLog b/ChangeLog
+index e691b241..74eea81f 100644
+--- a/ChangeLog
++++ b/ChangeLog
+@@ -1,3 +1,12 @@
++2026-04-06         Arnold D. Robbins     <arnold@skeeve.com>
++
++	* builtin.c (do_sub): Check for overflow in calculation of size
++	of result buffer by doing the math in 64 bits. This provides
++	a fatal message on 32 bit systems if overflow happens instead
++	of letting dynamic memory get corrupted and likely causing
++	a core dump. Thanks to MichaƂ Majchrowicz <mmajchrowicz@afine.com>
++	for the report and fix.
++
+ 2026-04-04         Arnold D. Robbins     <arnold@skeeve.com>
+ 
+ 	* builtin.c (do_sub): Make `sofar' be size_t to avoid
+diff --git a/builtin.c b/builtin.c
+index 80ab6069..d63cf47b 100644
+--- a/builtin.c
++++ b/builtin.c
+@@ -2998,11 +2998,13 @@ do_sub(int nargs, unsigned int flags)
+ 	long current;
+ 	bool lastmatchnonzero;
+ 	char *mb_indices = NULL;
++	const char *fname = NULL;	// for fatal message, below
+ 
+ 	if ((flags & GENSUB) != 0) {
+ 		double d;
+ 		NODE *glob_flag;
+ 
++		fname = "gensub";
+ 		check_exact_args(nargs, "gensub", 4);
+ 
+ 		tmp = PEEK(3);
+@@ -3033,11 +3035,9 @@ do_sub(int nargs, unsigned int flags)
+ 		}
+ 		DEREF(glob_flag);
+ 	} else {
+-		if ((flags & GSUB) != 0) {
+-			check_exact_args(nargs, "gsub", 3);
+-		} else {
+-			check_exact_args(nargs, "sub", 3);
+-		}
++		fname = ((flags & GSUB) != 0) ? "gsub" : "sub";
++
++		check_exact_args(nargs, fname, 3);
+ 
+ 		/* take care of regexp early, in case re_update is fatal */
+ 
+@@ -3153,6 +3153,21 @@ do_sub(int nargs, unsigned int flags)
+ 		 * vary since ampersand is actual text of regexp match.
+ 		 */
+ 
++		// 4/2026: This overflow check simply provides a fatal
++		// message instead of letting realloc() die later after
++		// a buffer overrun.  It simply makes the user experience better,
++		// but does not prevent gawk from dying miserably.  I suppose
++		// it's worth the trouble, but just barely.
++
++		/* uint64_t so the product is 64-bit even on 32-bit ILP32 builds */
++		uint64_t repl_contribution =
++			(uint64_t)(unsigned int)ampersands
++			* (uint64_t)(uintptr_t)(matchend - matchstart);
++		if (repl_contribution > (uint64_t)SIZE_MAX
++		    || repl_contribution > (uint64_t)SIZE_MAX - (size_t)(matchend - text)
++						- repllen - 1)
++			fatal(_("%s: replacement expansion too large"), fname);
++
+ 		/*
+ 		 * add 1 to len to handle "empty" case where
+ 		 * matchend == matchstart and we force a match on a single
+-- 
+2.44.4
+
diff --git a/meta/recipes-extended/gawk/gawk_5.3.0.bb b/meta/recipes-extended/gawk/gawk_5.3.0.bb
index d79b0222a6..7bd34a3ff8 100644
--- a/meta/recipes-extended/gawk/gawk_5.3.0.bb
+++ b/meta/recipes-extended/gawk/gawk_5.3.0.bb
@@ -24,6 +24,7 @@  SRC_URI = "${GNU_MIRROR}/gawk/gawk-${PV}.tar.gz \
            file://0001-Fix-some-C23-compilatio-issues.patch \
            file://CVE-2026-40467.patch \
            file://CVE-2026-40468.patch \
+           file://CVE-2026-40469.patch \
            "
 
 SRC_URI[sha256sum] = "378f8864ec21cfceaa048f7e1869ac9b4597b449087caf1eb55e440d30273336"