[linux] 01/01: vfs: ioctl: prevent double-fetch in dedupe ioctl (CVE-2016-6516)

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carnil pushed a commit to branch sid
in repository linux.

commit c2a8f662b5441720a38317993576dd2f2a52060e
Author: Salvatore Bonaccorso <carnil at debian.org>
Date:   Tue Aug 2 06:46:45 2016 +0200

    vfs: ioctl: prevent double-fetch in dedupe ioctl (CVE-2016-6516)
---
 debian/changelog                                   |  3 +++
 ...octl-prevent-double-fetch-in-dedupe-ioctl.patch | 30 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 3 files changed, 34 insertions(+)

diff --git a/debian/changelog b/debian/changelog
index ecc53d7..eca0796 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -210,6 +210,9 @@ linux (4.6.5-1) UNRELEASED; urgency=medium
   * Fix perf to be able to find debug info based on build-id. (Closes:
     #833096)
 
+  [ Salvatore Bonaccorso ]
+  * vfs: ioctl: prevent double-fetch in dedupe ioctl (CVE-2016-6516)
+
  -- Ben Hutchings <ben at decadent.org.uk>  Sat, 30 Jul 2016 14:23:58 +0100
 
 linux (4.6.4-1) unstable; urgency=medium
diff --git a/debian/patches/bugfix/all/vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch b/debian/patches/bugfix/all/vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch
new file mode 100644
index 0000000..7e90e8c
--- /dev/null
+++ b/debian/patches/bugfix/all/vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch
@@ -0,0 +1,30 @@
+From: Scott Bauer <sbauer at plzdonthack.me>
+Date: Wed, 27 Jul 2016 19:11:29 -0600
+Subject: vfs: ioctl: prevent double-fetch in dedupe ioctl
+Origin: https://git.kernel.org/linus/10eec60ce79187686e052092e5383c99b4420a20
+
+This prevents a double-fetch from user space that can lead to to an
+undersized allocation and heap overflow.
+
+Fixes: 54dbc1517237 ("vfs: hoist the btrfs deduplication ioctl to the vfs")
+Signed-off-by: Scott Bauer <sbauer at plzdonthack.me>
+Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
+---
+ fs/ioctl.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/fs/ioctl.c b/fs/ioctl.c
+index 116a333..0f56deb 100644
+--- a/fs/ioctl.c
++++ b/fs/ioctl.c
+@@ -590,6 +590,7 @@ static long ioctl_file_dedupe_range(struct file *file, void __user *arg)
+ 		goto out;
+ 	}
+ 
++	same->dest_count = count;
+ 	ret = vfs_dedupe_file_range(file, same);
+ 	if (ret)
+ 		goto out;
+-- 
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index 14f6244..17ae971 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -107,6 +107,7 @@ bugfix/all/alsa-timer-fix-leak-in-events-via-snd_timer_user_cca.patch
 bugfix/all/alsa-timer-fix-leak-in-events-via-snd_timer_user_tin.patch
 bugfix/all/tipc-fix-an-infoleak-in-tipc_nl_compat_link_dump.patch
 bugfix/all/rds-fix-an-infoleak-in-rds_inc_info_copy.patch
+bugfix/all/vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch
 
 # ABI maintenance
 debian/mips-siginfo-fix-abi-change-in-4.6.2.patch

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