net-snmp: Fix CVE-2020-15861 and CVE-2020-15862

Net-SNMP through 5.7.3 allows Escalation of Privileges because of UNIX symbolic
link (symlink) following.

Net-SNMP through 5.7.3 has Improper Privilege Management because SNMP WRITE
access to the EXTEND MIB provides the ability to run arbitrary commands as
root.

References:
https://nvd.nist.gov/vuln/detail/CVE-2020-15861
https://nvd.nist.gov/vuln/detail/CVE-2020-15862

Upstream patches:
https://github.com/net-snmp/net-snmp/commit/2b3e300ade4add03b889e61d610b0db77d300fc3
https://github.com/net-snmp/net-snmp/commit/9cfb38b0aa95363da1466ca81dd929989ba27c1f
https://github.com/net-snmp/net-snmp/commit/114e4c2cec2601ca56e8afb1f441520f75a9a312
https://github.com/net-snmp/net-snmp/commit/2968b455e6f182f329746e2bca1043f368618c73
https://github.com/net-snmp/net-snmp/commit/4fd9a450444a434a993bc72f7c3486ccce41f602
https://github.com/net-snmp/net-snmp/commit/77f6c60f57dba0aaea5d8ef1dd94bcd0c8e6d205

CVE-2020-15861-0005.patch is the actual fix for CVE-2020-15861 and
CVE-2020-15861-0001.patch through CVE-2020-15861-0004.patch are context
patches needed by the fix to apply cleanly.

Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/meta-networking/recipes-protocols/net-snmp/net-snmp/CVE-2020-15861-0002.patch b/meta-networking/recipes-protocols/net-snmp/net-snmp/CVE-2020-15861-0002.patch
new file mode 100644
index 0000000000..e54a8b4acb
--- /dev/null
+++ b/meta-networking/recipes-protocols/net-snmp/net-snmp/CVE-2020-15861-0002.patch
@@ -0,0 +1,44 @@
+From 50118392c58c8d9554580373c0dbc542336b58a9 Mon Sep 17 00:00:00 2001
+From: Bart Van Assche <bvanassche@acm.org>
+Date: Thu, 16 May 2019 13:49:05 +0200
+Subject: [PATCH 2/5] libsnmp: Fix two recently introduced issues in the MIB
+ parsing code
+
+Ensure that the first argument passed to qsort() is not NULL. Free the memory
+that holds the directory contents.
+
+Fixes: 2b3e300ade4a ("CHANGES: libsnmp: Scan MIB directories in alphabetical order")
+
+CVE: CVE-2020-15861
+Upstream-Status: Backport [https://github.com/net-snmp/net-snmp/commit/9cfb38b0aa95363da1466ca81dd929989ba27c1f]
+
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+---
+ snmplib/parse.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/snmplib/parse.c b/snmplib/parse.c
+index 51d119b..200ba25 100644
+--- a/snmplib/parse.c
++++ b/snmplib/parse.c
+@@ -4961,7 +4961,8 @@ static int scan_directory(char ***result, const char *dirname)
+     }
+     closedir(dir);
+ 
+-    qsort(filenames, filename_count, sizeof(filenames[0]), elemcmp);
++    if (filenames)
++        qsort(filenames, filename_count, sizeof(filenames[0]), elemcmp);
+     *result = filenames;
+ 
+     return filename_count;
+@@ -5040,6 +5041,7 @@ add_mibdir(const char *dirname)
+         File = oldFile;
+         if (ip)
+             fclose(ip);
++        free(filenames);
+         return (count);
+     }
+     else
+-- 
+2.17.1
+