libarchive: fix CVE-2025-5917

A vulnerability has been identified in the libarchive library. This flaw involves an 'off-by-
one' miscalculation when handling prefixes and suffixes for file names. This can lead to a 1-
byte write overflow. While seemingly small, such an overflow can corrupt adjacent memory, lea
ding to unpredictable program behavior, crashes, or in specific circumstances, could be lever
aged as a building block for more sophisticated exploitation.

Reference:
https://security-tracker.debian.org/tracker/CVE-2025-5917

Upstream-patch:
https://github.com/libarchive/libarchive/commit/7c02cde37a63580cd1859183fbbd2cf04a89be85

(From OE-Core rev: 2b6832b05bab414df1da7c74a0c6a5e5a9d75b29)

Signed-off-by: Divya Chellam <divya.chellam@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 55 insertions, 0 deletions

diff --git a/meta/recipes-extended/libarchive/libarchive/CVE-2025-5917.patch b/meta/recipes-extended/libarchive/libarchive/CVE-2025-5917.patch
new file mode 100644
index 0000000000..28f7b6023a
--- /dev/null
+++ b/meta/recipes-extended/libarchive/libarchive/CVE-2025-5917.patch
@@ -0,0 +1,54 @@
+From 7c02cde37a63580cd1859183fbbd2cf04a89be85 Mon Sep 17 00:00:00 2001
+From: Brian Campbell <Brian.Campbell@ed.ac.uk>
+Date: Sat, 26 Apr 2025 05:11:19 +0100
+Subject: [PATCH] Fix overflow in build_ustar_entry (#2588)
+
+The calculations for the suffix and prefix can increment the endpoint
+for a trailing slash. Hence the limits used should be one lower than the
+maximum number of bytes.
+
+Without this patch, when this happens for both the prefix and the
+suffix, we end up with 156 + 100 bytes, and the write of the null at the
+end will overflow the 256 byte buffer. This can be reproduced by running
+```
+mkdir -p foo/bar
+bsdtar cvf test.tar foo////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////bar
+```
+when bsdtar is compiled with Address Sanitiser, although I originally
+noticed this by accident with a genuine filename on a CHERI capability
+system, which faults immediately on the buffer overflow.
+
+CVE: CVE-2025-5917
+
+Upstream-Status: Backport [https://github.com/libarchive/libarchive/commit/7c02cde37a63580cd1859183fbbd2cf04a89be85]
+
+Signed-off-by: Divya Chellam <divya.chellam@windriver.com>
+---
+ libarchive/archive_write_set_format_pax.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/libarchive/archive_write_set_format_pax.c b/libarchive/archive_write_set_format_pax.c
+index 6e35f70..b2ba959 100644
+--- a/libarchive/archive_write_set_format_pax.c
++++ b/libarchive/archive_write_set_format_pax.c
+@@ -1571,7 +1571,7 @@ build_ustar_entry_name(char *dest, const char *src, size_t src_length,
+        const char *filename, *filename_end;
+        char *p;
+        int need_slash = 0; /* Was there a trailing slash? */
+-       size_t suffix_length = 99;
++       size_t suffix_length = 98; /* 99 - 1 for trailing slash */
+        size_t insert_length;
+ 
+        /* Length of additional dir element to be added. */
+@@ -1623,7 +1623,7 @@ build_ustar_entry_name(char *dest, const char *src, size_t src_length,
+        /* Step 2: Locate the "prefix" section of the dirname, including
+         * trailing '/'. */
+        prefix = src;
+-       prefix_end = prefix + 155;
++       prefix_end = prefix + 154 /* 155 - 1 for trailing / */;
+        if (prefix_end > filename)
+                prefix_end = filename;
+        while (prefix_end > prefix && *prefix_end != '/')
+-- 
+2.40.0
+
diff --git a/meta/recipes-extended/libarchive/libarchive_3.7.9.bb b/meta/recipes-extended/libarchive/libarchive_3.7.9.bb
index 250a3c016f..bb8609dd09 100644
--- a/meta/recipes-extended/libarchive/libarchive_3.7.9.bb
+++ b/meta/recipes-extended/libarchive/libarchive_3.7.9.bb
@@ -34,6 +34,7 @@ SRC_URI = "http://libarchive.org/downloads/libarchive-${PV}.tar.gz \
            file://CVE-2025-5914.patch \
            file://CVE-2025-5915.patch \
            file://CVE-2025-5916.patch \
+           file://CVE-2025-5917.patch \
            "
 UPSTREAM_CHECK_URI = "http://libarchive.org/"