package/musl: add upstream security fixes for CVE-2025-26519

Fixes CVE-2025-26519: Musl libc: input-controlled out-of-bounds write
primitive in iconv()

https://www.openwall.com/lists/musl/2025/02/13/1

Fixes:
https://nvd.nist.gov/vuln/detail/CVE-2025-26519

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
[Julien: add link to cve]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/musl/0004-iconv-fix-erroneous-input-validation-in-EUC-KR-decod.patch

@@ -0,0 +1,41 @@
+From e5adcd97b5196e29991b524237381a0202a60659 Mon Sep 17 00:00:00 2001
+From: Rich Felker <dalias@aerifal.cx>
+Date: Sun, 9 Feb 2025 10:07:19 -0500
+Subject: [PATCH] iconv: fix erroneous input validation in EUC-KR decoder
+
+as a result of incorrect bounds checking on the lead byte being
+decoded, certain invalid inputs which should produce an encoding
+error, such as "\xc8\x41", instead produced out-of-bounds loads from
+the ksc table.
+
+in a worst case, the loaded value may not be a valid unicode scalar
+value, in which case, if the output encoding was UTF-8, wctomb would
+return (size_t)-1, causing an overflow in the output pointer and
+remaining buffer size which could clobber memory outside of the output
+buffer.
+
+bug report was submitted in private by Nick Wellnhofer on account of
+potential security implications.
+
+Upstream: https://git.musl-libc.org/cgit/musl/commit/?id=e5adcd97b5196e29991b524237381a0202a60659
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ src/locale/iconv.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/locale/iconv.c b/src/locale/iconv.c
+index 9605c8e9..008c93f0 100644
+--- a/src/locale/iconv.c
++++ b/src/locale/iconv.c
+@@ -502,7 +502,7 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
+ 			if (c >= 93 || d >= 94) {
+ 				c += (0xa1-0x81);
+ 				d += 0xa1;
+-				if (c >= 93 || c>=0xc6-0x81 && d>0x52)
++				if (c > 0xc6-0x81 || c==0xc6-0x81 && d>0x52)
+ 					goto ilseq;
+ 				if (d-'A'<26) d = d-'A';
+ 				else if (d-'a'<26) d = d-'a'+26;
+-- 
+2.39.5
+

package/musl/0005-iconv-harden-UTF-8-output-code-path-against-input-de.patch

@@ -0,0 +1,40 @@
+From c47ad25ea3b484e10326f933e927c0bc8cded3da Mon Sep 17 00:00:00 2001
+From: Rich Felker <dalias@aerifal.cx>
+Date: Wed, 12 Feb 2025 17:06:30 -0500
+Subject: [PATCH] iconv: harden UTF-8 output code path against input decoder
+ bugs
+
+the UTF-8 output code was written assuming an invariant that iconv's
+decoders only emit valid Unicode Scalar Values which wctomb can encode
+successfully, thereby always returning a value between 1 and 4.
+
+if this invariant is not satisfied, wctomb returns (size_t)-1, and the
+subsequent adjustments to the output buffer pointer and remaining
+output byte count overflow, moving the output position backwards,
+potentially past the beginning of the buffer, without storing any
+bytes.
+
+Upstream: https://git.musl-libc.org/cgit/musl/commit/?id=c47ad25ea3b484e10326f933e927c0bc8cded3da
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ src/locale/iconv.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/src/locale/iconv.c b/src/locale/iconv.c
+index 008c93f0..52178950 100644
+--- a/src/locale/iconv.c
++++ b/src/locale/iconv.c
+@@ -545,6 +545,10 @@ size_t iconv(iconv_t cd, char **restrict in, size_t *restrict inb, char **restri
+ 				if (*outb < k) goto toobig;
+ 				memcpy(*out, tmp, k);
+ 			} else k = wctomb_utf8(*out, c);
++			/* This failure condition should be unreachable, but
++			 * is included to prevent decoder bugs from translating
++			 * into advancement outside the output buffer range. */
++			if (k>4) goto ilseq;
+ 			*out += k;
+ 			*outb -= k;
+ 			break;
+-- 
+2.39.5
+

package/musl/musl.mk

@@ -26,6 +26,10 @@ MUSL_ADD_TOOLCHAIN_DEPENDENCY = NO
 
 MUSL_INSTALL_STAGING = YES
 
+# 0004-iconv-fix-erroneous-input-validation-in-EUC-KR-decod.patch
+# 0005-iconv-harden-UTF-8-output-code-path-against-input-de.patch
+MUSL_IGNORE_CVES += CVE-2025-26519
+
 # musl does not build with LTO, so explicitly disable it
 # when using a compiler that may have support for LTO
 ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_4_7),y)