Muehlenhoff has uploaded a new change for review.
https://gerrit.wikimedia.org/r/316614
Change subject: Add patch for CVE-2016-7042
......................................................................
Add patch for CVE-2016-7042
Change-Id: I92d77e50770ba459b99e4ba434cc810bc1b4f45f
---
M debian/changelog
A debian/patches/bugfix/all/CVE-2016-7042.patch
M debian/patches/series
3 files changed, 62 insertions(+), 1 deletion(-)
git pull ssh://gerrit.wikimedia.org:29418/operations/debs/linux44
refs/changes/14/316614/1
diff --git a/debian/changelog b/debian/changelog
index e279c41..652b851 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -19,8 +19,10 @@
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.24
* Update to 4.4.25:
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.25
+ * Add patch by Vladis Dronov to address CVE-2016-7042 (not yet
+ merged upstream)
- -- Moritz Muehlenhoff <mmuhlenh...@wikimedia.org> Mon, 17 Oct 2016 10:00:33
+0200
+ -- Moritz Muehlenhoff <mmuhlenh...@wikimedia.org> Tue, 18 Oct 2016 21:33:33
+0200
linux (4.4.2-3+wmf5) jessie-wikimedia; urgency=medium
diff --git a/debian/patches/bugfix/all/CVE-2016-7042.patch
b/debian/patches/bugfix/all/CVE-2016-7042.patch
new file mode 100644
index 0000000..5257ea9
--- /dev/null
+++ b/debian/patches/bugfix/all/CVE-2016-7042.patch
@@ -0,0 +1,58 @@
+ KEYS: Fix short sprintf buffer in /proc/keys show function
+
+ Fix a short sprintf buffer in proc_keys_show(). If the gcc stack protector
+ is turned on, this can cause a panic due to stack corruption.
+
+ The problem is that xbuf[] is not big enough to hold a 64-bit timeout
+ rendered as weeks:
+
+ (gdb) p 0xffffffffffffffffULL/(60*60*24*7)
+ $2 = 30500568904943
+
+ That's 14 chars plus NUL, not 11 chars plus NUL.
+
+ Expand the buffer to 16 chars.
+
+ I think the unpatched code apparently works if the stack-protector is not
+ enabled because on a 32-bit machine the buffer won't be overflowed and on a
+ 64-bit machine there's a 64-bit aligned pointer at one side and an int that
+ isn't checked again on the other side.
+
+ The panic incurred looks something like:
+
+ Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in:
ffffffff81352ebe
+ CPU: 0 PID: 1692 Comm: reproducer Not tainted 4.7.2-201.fc24.x86_64 #1
+ Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
+ 0000000000000086 00000000fbbd2679 ffff8800a044bc00 ffffffff813d941f
+ ffffffff81a28d58 ffff8800a044bc98 ffff8800a044bc88 ffffffff811b2cb6
+ ffff880000000010 ffff8800a044bc98 ffff8800a044bc30 00000000fbbd2679
+ Call Trace:
+ [<ffffffff813d941f>] dump_stack+0x63/0x84
+ [<ffffffff811b2cb6>] panic+0xde/0x22a
+ [<ffffffff81352ebe>] ? proc_keys_show+0x3ce/0x3d0
+ [<ffffffff8109f7f9>] __stack_chk_fail+0x19/0x30
+ [<ffffffff81352ebe>] proc_keys_show+0x3ce/0x3d0
+ [<ffffffff81350410>] ? key_validate+0x50/0x50
+ [<ffffffff8134db30>] ? key_default_cmp+0x20/0x20
+ [<ffffffff8126b31c>] seq_read+0x2cc/0x390
+ [<ffffffff812b6b12>] proc_reg_read+0x42/0x70
+ [<ffffffff81244fc7>] __vfs_read+0x37/0x150
+ [<ffffffff81357020>] ? security_file_permission+0xa0/0xc0
+ [<ffffffff81246156>] vfs_read+0x96/0x130
+ [<ffffffff81247635>] SyS_read+0x55/0xc0
+ [<ffffffff817eb872>] entry_SYSCALL_64_fastpath+0x1a/0xa4
+
+ Reported-by: Ondrej Kozina <okoz...@redhat.com>
+ Signed-off-by: David Howells <dhowe...@redhat.com>
+ Tested-by: Ondrej Kozina <okoz...@redhat.com>
+--- a/security/keys/proc.c
++++ a/security/keys/proc.c
+@@ -181,7 +181,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
+ struct timespec now;
+ unsigned long timo;
+ key_ref_t key_ref, skey_ref;
+- char xbuf[12];
++ char xbuf[16];
+ int rc;
+
+ struct keyring_search_context ctx = {
diff --git a/debian/patches/series b/debian/patches/series
index 287c245..380b702 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -126,3 +126,4 @@
bugfix/all/stable-4.4.23.patch
bugfix/all/stable-4.4.24.patch
bugfix/all/stable-4.4.25.patch
+bugfix/all/CVE-2016-7042.patch
--
To view, visit https://gerrit.wikimedia.org/r/316614
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I92d77e50770ba459b99e4ba434cc810bc1b4f45f
Gerrit-PatchSet: 1
Gerrit-Project: operations/debs/linux44
Gerrit-Branch: master
Gerrit-Owner: Muehlenhoff <mmuhlenh...@wikimedia.org>
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