[Buildroot] [PATCH 2025.02.x] package/util-linux: backport patch CVE-2026-13595

- CVE-2026-13595:
    A flaw was found in the libblkid library of util-linux. During nested
    partition probing, the BSD, Minix, Solaris x86, and UnixWare partition
    probers cache a raw pointer to a parent partition entry in a
    dynamically allocated array. When subsequent partition additions cause
    the array to be reallocated, this pointer becomes stale, leading to a
    heap use-after-free read. An attacker who can present a crafted block
    device image (for example, via USB insertion or a loop-mounted disk
    image) can trigger this flaw without user interaction, as libblkid is
    invoked automatically by udev/udisks as root on block-device hot-plug
    events. This could lead to limited information disclosure or denial of
    service.

For more information, see:
 - https://www.cve.org/CVERecord?id=CVE-2026-13595
 - https://github.com/util-linux/util-linux/commit/c0186f14fbdb02f64c8e0ba701ce727ea764ff4c

Signed-off-by: Thomas Perale <[email protected]>
---
 package/util-linux/0015-CVE-2026-13595.patch | 145 +++++++++++++++++++
 package/util-linux/util-linux.mk             |   3 +
 2 files changed, 148 insertions(+)
 create mode 100644 package/util-linux/0015-CVE-2026-13595.patch

diff --git a/package/util-linux/0015-CVE-2026-13595.patch b/package/util-linux/0015-CVE-2026-13595.patch
new file mode 100644
index 0000000000..7547a20137
--- /dev/null
+++ b/package/util-linux/0015-CVE-2026-13595.patch
@@ -0,0 +1,145 @@
+From c0186f14fbdb02f64c8e0ba701ce727ea764ff4c Mon Sep 17 00:00:00 2001
+From: Karel Zak <[email protected]>
+Date: Thu, 7 May 2026 12:50:48 +0200
+Subject: [PATCH] libblkid: fix use-after-free in nested partition probing
+
+The partitions list stores partitions in a contiguous array grown by
+reallocarray(). When the array is reallocated to a new address, all
+existing blkid_partition pointers (tab->parent, ls->next_parent, local
+parent variables in nested probers) become dangling.
+
+Fix this by changing the storage from an array of structs to an array
+of pointers, where each partition is individually allocated via
+calloc(). This makes all blkid_partition pointers stable across
+reallocations -- only the pointer array itself may move, which is
+harmless since no code caches pointers into the pointer array.
+
+This eliminates the need for callers to re-fetch parent pointers after
+every blkid_partlist_add_partition() call.
+
+Reported-by: Thai Duong <[email protected]>
+Signed-off-by: Karel Zak <[email protected]>
+CVE: CVE-2026-13595
+Upstream: https://github.com/util-linux/util-linux/commit/c0186f14fbdb02f64c8e0ba701ce727ea764ff4c
+Signed-off-by: Thomas Perale <[email protected]>
+---
+ libblkid/src/partitions/partitions.c | 34 +++++++++++++++++-----------
+ 1 file changed, 21 insertions(+), 13 deletions(-)
+
+diff --git a/libblkid/src/partitions/partitions.c b/libblkid/src/partitions/partitions.c
+index f95fe898f33..a428c6d6c16 100644
+--- a/libblkid/src/partitions/partitions.c
++++ b/libblkid/src/partitions/partitions.c
+@@ -197,7 +197,7 @@ struct blkid_struct_partlist {
+ 
+ 	int		nparts;		/* number of partitions */
+ 	int		nparts_max;	/* max.number of partitions */
+-	blkid_partition	parts;		/* array of partitions */
++	blkid_partition	*parts;		/* array of pointers to partitions */
+ 
+ 	struct list_head l_tabs;	/* list of partition tables */
+ };
+@@ -356,13 +356,16 @@ static void reset_partlist(blkid_partlist ls)
+ 	free_parttables(ls);
+ 
+ 	if (ls->next_partno) {
+-		/* already initialized - reset */
+-		int tmp_nparts = ls->nparts_max;
+-		blkid_partition tmp_parts = ls->parts;
++		/* already initialized - free individually allocated partitions */
++		int i, tmp_nparts_max = ls->nparts_max;
++		blkid_partition *tmp_parts = ls->parts;
++
++		for (i = 0; i < ls->nparts; i++)
++			free(ls->parts[i]);
+ 
+ 		memset(ls, 0, sizeof(struct blkid_struct_partlist));
+ 
+-		ls->nparts_max = tmp_nparts;
++		ls->nparts_max = tmp_nparts_max;
+ 		ls->parts = tmp_parts;
+ 	}
+ 
+@@ -397,6 +400,7 @@ static void partitions_free_data(blkid_probe pr __attribute__((__unused__)),
+ 				 void *data)
+ {
+ 	blkid_partlist ls = (blkid_partlist) data;
++	int i;
+ 
+ 	if (!ls)
+ 		return;
+@@ -404,6 +408,8 @@ static void partitions_free_data(blkid_probe pr __attribute__((__unused__)),
+ 	free_parttables(ls);
+ 
+ 	/* deallocate partitions and partlist */
++	for (i = 0; i < ls->nparts; i++)
++		free(ls->parts[i]);
+ 	free(ls->parts);
+ 	free(ls);
+ }
+@@ -437,15 +443,17 @@ static blkid_partition new_partition(blkid_partlist ls, blkid_parttable tab)
+ 		 * generic Linux machine -- let start with 32 partitions.
+ 		 */
+ 		void *tmp = reallocarray(ls->parts, ls->nparts_max + 32,
+-					 sizeof(struct blkid_struct_partition));
++					 sizeof(blkid_partition));
+ 		if (!tmp)
+ 			return NULL;
+ 		ls->parts = tmp;
+ 		ls->nparts_max += 32;
+ 	}
+ 
+-	par = &ls->parts[ls->nparts++];
+-	memset(par, 0, sizeof(struct blkid_struct_partition));
++	par = calloc(1, sizeof(struct blkid_struct_partition));
++	if (!par)
++		return NULL;
++	ls->parts[ls->nparts++] = par;
+ 
+ 	ref_parttable(tab);
+ 	par->tab = tab;
+@@ -850,7 +858,7 @@ int blkid_probe_is_covered_by_pt(blkid_probe pr,
+ 
+ 	/* check if the partition table fits into the device */
+ 	for (i = 0; i < nparts; i++) {
+-		blkid_partition par = &ls->parts[i];
++		blkid_partition par = ls->parts[i];
+ 
+ 		if (par->start + par->size > (pr->size >> 9)) {
+ 			DBG(LOWPROBE, ul_debug("partition #%d overflows "
+@@ -862,7 +870,7 @@ int blkid_probe_is_covered_by_pt(blkid_probe pr,
+ 
+ 	/* check if the requested area is covered by PT */
+ 	for (i = 0; i < nparts; i++) {
+-		blkid_partition par = &ls->parts[i];
++		blkid_partition par = ls->parts[i];
+ 
+ 		if (start >= par->start && end <= par->start + par->size) {
+ 			rc = 1;
+@@ -961,7 +969,7 @@ blkid_partition blkid_partlist_get_partition(blkid_partlist ls, int n)
+ 	if (n < 0 || n >= ls->nparts)
+ 		return NULL;
+ 
+-	return &ls->parts[n];
++	return ls->parts[n];
+ }
+ 
+ blkid_partition blkid_partlist_get_partition_by_start(blkid_partlist ls, uint64_t start)
+@@ -1073,7 +1081,7 @@ blkid_partition blkid_partlist_devno_to_partition(blkid_partlist ls, dev_t devno
+ 		 * and an entry in partition table.
+ 		 */
+ 		 for (i = 0; i < ls->nparts; i++) {
+-			 blkid_partition par = &ls->parts[i];
++			 blkid_partition par = ls->parts[i];
+ 
+ 			 if (partno != blkid_partition_get_partno(par))
+ 				 continue;
+@@ -1089,7 +1097,7 @@ blkid_partition blkid_partlist_devno_to_partition(blkid_partlist ls, dev_t devno
+ 	DBG(LOWPROBE, ul_debug("searching by offset/size"));
+ 
+ 	for (i = 0; i < ls->nparts; i++) {
+-		blkid_partition par = &ls->parts[i];
++		blkid_partition par = ls->parts[i];
+ 
+ 		if ((uint64_t)blkid_partition_get_start(par) == start &&
+ 		    (uint64_t)blkid_partition_get_size(par) == size)
diff --git a/package/util-linux/util-linux.mk b/package/util-linux/util-linux.mk
index b5364b710b..9e56894611 100644
--- a/package/util-linux/util-linux.mk
+++ b/package/util-linux/util-linux.mk
@@ -54,6 +54,9 @@ UTIL_LINUX_IGNORE_CVES += CVE-2026-53613
 # 0013-CVE-2026-53614.patch
 UTIL_LINUX_IGNORE_CVES += CVE-2026-53614
 
+# 0015-CVE-2026-13595.patch
+UTIL_LINUX_IGNORE_CVES += CVE-2026-13595
+
 UTIL_LINUX_INSTALL_STAGING = YES
 UTIL_LINUX_DEPENDENCIES = \
 	host-pkgconf \
-- 
2.55.0

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