5 files changed, 42 insertions, 3 deletions

diff --git a/debian/.git-dpm b/debian/.git-dpm
index 9ddb5b008..39a4a89ba 100644
--- a/debian/.git-dpm
+++ b/debian/.git-dpm
@@ -1,6 +1,6 @@
 # see git-dpm(1) from git-dpm package
-a0f9daa9c3cc2b37b9707b228263eb717d201371
-a0f9daa9c3cc2b37b9707b228263eb717d201371
+35b2ea77a74348b575d680061f35ec7992b26ec8
+35b2ea77a74348b575d680061f35ec7992b26ec8
 971a7653746a6972b907dfe0ce139c06e4a6f482
 971a7653746a6972b907dfe0ce139c06e4a6f482
 openssh_7.4p1.orig.tar.gz
diff --git a/debian/changelog b/debian/changelog
index 6d6a0f817..1b4a2d1f8 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+openssh (1:7.4p1-9) UNRELEASED; urgency=medium
+
+  * Fix null pointer dereference in ssh-keygen; this fixes an autopkgtest
+    regression introduced in 1:7.4p1-8.
+
+ -- Colin Watson <cjwatson@debian.org>  Thu, 16 Mar 2017 13:42:24 +0000
+
 openssh (1:7.4p1-8) unstable; urgency=medium
 
   * Fix ssh-keygen -H accidentally corrupting known_hosts that contained
diff --git a/debian/patches/series b/debian/patches/series
index 2d9d2bc12..32f913e89 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -32,3 +32,4 @@ no-dsa-host-key-by-default.patch
 restore-authorized_keys2.patch
 ssh-keygen-hash-corruption.patch
 ssh-keyscan-hash-port.patch
+ssh-keygen-null-deref.patch
diff --git a/debian/patches/ssh-keygen-null-deref.patch b/debian/patches/ssh-keygen-null-deref.patch
new file mode 100644
index 000000000..0220d7c66
--- /dev/null
+++ b/debian/patches/ssh-keygen-null-deref.patch
@@ -0,0 +1,31 @@
+From 35b2ea77a74348b575d680061f35ec7992b26ec8 Mon Sep 17 00:00:00 2001
+From: "dtucker@openbsd.org" <dtucker@openbsd.org>
+Date: Mon, 6 Mar 2017 02:03:20 +0000
+Subject: upstream commit
+
+Check l->hosts before dereferencing; fixes potential null
+pointer deref. ok djm@
+
+Upstream-ID: 81c0327c6ec361da794b5c680601195cc23d1301
+
+Origin: https://anongit.mindrot.org/openssh.git/commit/?id=18501151cf272a15b5f2c5e777f2e0933633c513
+Last-Update: 2017-03-16
+
+Patch-Name: ssh-keygen-null-deref.patch
+---
+ ssh-keygen.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/ssh-keygen.c b/ssh-keygen.c
+index 0833ee61..a7c1e80b 100644
+--- a/ssh-keygen.c
++++ b/ssh-keygen.c
+@@ -1082,7 +1082,7 @@ known_hosts_hash(struct hostkey_foreach_line *l, void *_ctx)
+        struct known_hosts_ctx *ctx = (struct known_hosts_ctx *)_ctx;
+        char *hashed, *cp, *hosts, *ohosts;
+        int has_wild = l->hosts && strcspn(l->hosts, "*?!") != strlen(l->hosts);
+-       int was_hashed = l->hosts[0] == HASH_DELIM;
++       int was_hashed = l->hosts && l->hosts[0] == HASH_DELIM;
+ 
+        switch (l->status) {
+        case HKF_STATUS_OK:
diff --git a/ssh-keygen.c b/ssh-keygen.c
index 0833ee61d..a7c1e80b9 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1082,7 +1082,7 @@ known_hosts_hash(struct hostkey_foreach_line *l, void *_ctx)
         struct known_hosts_ctx *ctx = (struct known_hosts_ctx *)_ctx;
         char *hashed, *cp, *hosts, *ohosts;
         int has_wild = l->hosts && strcspn(l->hosts, "*?!") != strlen(l->hosts);
-        int was_hashed = l->hosts[0] == HASH_DELIM;
+        int was_hashed = l->hosts && l->hosts[0] == HASH_DELIM;
 
         switch (l->status) {
         case HKF_STATUS_OK: