patches: libopkg: fix md5sum calculation

1 files changed, 51 insertions, 0 deletions

diff --git a/patches/libopkg-fix-md5sum-calculation.patch b/patches/libopkg-fix-md5sum-calculation.patch
new file mode 100644
index 0000000..71107c5
--- /dev/null
+++ b/patches/libopkg-fix-md5sum-calculation.patch
@@ -0,0 +1,51 @@
+From 66f458decf9fd2839d77bf420e93d9c78025488a Mon Sep 17 00:00:00 2001
+From: Alexander Ryzhov <github@ryzhov-al.ru>
+Date: Sun, 13 Sep 2020 14:42:56 +0200
+Subject: [PATCH] libopkg: fix md5sum calculation
+
+This regression prevents MD5 checksums from being checked. Packages are
+still installed, but this raises several issues:
+
+- if only MD5 checksums are provided in the package list, it is trivial
+  for an attacker to modify the content of a package, since checksum
+  verification is bypassed. If both MD5 and SHA256 checksums are
+  provided, then SHA256 is correctly verified and the attack is not
+  possible.
+
+- future efforts to harden checksum verification would prevent package
+  installation.
+
+Note that OpenWrt has switched to SHA256 for all its packages several
+years ago. As a result, this bug does not affect OpenWrt packages from the
+official package feeds.
+
+However, custom package repositories that only use MD5 are affected.
+
+Initially submitted at https://github.com/openwrt/openwrt/pull/3087
+
+Fixes: 33f7b80aa325 ("libopkg: drop custom md5 implementation,
+unconditionally enable sha256 support")
+
+Signed-off-by: Alexander Ryzhov <github@ryzhov-al.ru>
+[Add commit description]
+Signed-off-by: Baptiste Jonglez <git@bitsofnetworks.org>
+---
+ libopkg/file_util.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/libopkg/file_util.c b/libopkg/file_util.c
+index 3a1761e..8e698cc 100644
+--- a/libopkg/file_util.c
++++ b/libopkg/file_util.c
+@@ -153,7 +153,7 @@ char *file_md5sum_alloc(const char *file_name)
+ 
+ 	len = md5sum(file_name, md5sum_bin);
+ 
+-	if (len) {
++	if (len < 0) {
+ 		opkg_msg(ERROR, "Could't compute md5sum for %s.\n", file_name);
+ 		return NULL;
+ 	}
+-- 
+2.20.1
+