4.4-stable patches

added patches:
	bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch

diff --git a/queue-4.4/bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch b/queue-4.4/bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch
new file mode 100644 (file)
index 0000000..cd780b9
--- /dev/null
+++ b/queue-4.4/bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch
@@ -0,0 +1,60 @@
+From e4d4d456436bfb2fe412ee2cd489f7658449b098 Mon Sep 17 00:00:00 2001
+From: Piotr Krysiuk <piotras@gmail.com>
+Date: Mon, 5 Apr 2021 22:52:15 +0100
+Subject: bpf, x86: Validate computation of branch displacements for x86-64
+
+From: Piotr Krysiuk <piotras@gmail.com>
+
+commit e4d4d456436bfb2fe412ee2cd489f7658449b098 upstream.
+
+The branch displacement logic in the BPF JIT compilers for x86 assumes
+that, for any generated branch instruction, the distance cannot
+increase between optimization passes.
+
+But this assumption can be violated due to how the distances are
+computed. Specifically, whenever a backward branch is processed in
+do_jit(), the distance is computed by subtracting the positions in the
+machine code from different optimization passes. This is because part
+of addrs[] is already updated for the current optimization pass, before
+the branch instruction is visited.
+
+And so the optimizer can expand blocks of machine code in some cases.
+
+This can confuse the optimizer logic, where it assumes that a fixed
+point has been reached for all machine code blocks once the total
+program size stops changing. And then the JIT compiler can output
+abnormal machine code containing incorrect branch displacements.
+
+To mitigate this issue, we assert that a fixed point is reached while
+populating the output image. This rejects any problematic programs.
+The issue affects both x86-32 and x86-64. We mitigate separately to
+ease backporting.
+
+Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
+Reviewed-by: Daniel Borkmann <daniel@iogearbox.net>
+Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/net/bpf_jit_comp.c |   11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/net/bpf_jit_comp.c
++++ b/arch/x86/net/bpf_jit_comp.c
+@@ -1038,7 +1038,16 @@ common_load:
+               }
+ 
+               if (image) {
+-                      if (unlikely(proglen + ilen > oldproglen)) {
++                      /*
++                       * When populating the image, assert that:
++                       *
++                       *  i) We do not write beyond the allocated space, and
++                       * ii) addrs[i] did not change from the prior run, in order
++                       *     to validate assumptions made for computing branch
++                       *     displacements.
++                       */
++                      if (unlikely(proglen + ilen > oldproglen ||
++                                   proglen + ilen != addrs[i])) {
+                               pr_err("bpf_jit_compile fatal error\n");
+                               return -EFAULT;
+                       }

diff --git a/queue-4.4/cifs-silently-ignore-unknown-oplock-break-handle.patch b/queue-4.4/cifs-silently-ignore-unknown-oplock-break-handle.patch
index 67c6fe5505f552b2cf3acbcfa0d719c20c1cd722..de5df26d828afae996a06213fedc8e1e035c6d6c 100644 (file)
--- a/queue-4.4/cifs-silently-ignore-unknown-oplock-break-handle.patch
+++ b/queue-4.4/cifs-silently-ignore-unknown-oplock-break-handle.patch
@@ -30,14 +30,12 @@ Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
 Signed-off-by: Steve French <stfrench@microsoft.com>
 Signed-off-by: Sasha Levin <sashal@kernel.org>
 ---
- fs/cifs/smb2misc.c | 4 ++--
+ fs/cifs/smb2misc.c |    4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)
 
-diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
-index 44198b9a5315..19baeb4ca511 100644
 --- a/fs/cifs/smb2misc.c
 +++ b/fs/cifs/smb2misc.c
-@@ -633,8 +633,8 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
+@@ -633,8 +633,8 @@ smb2_is_valid_oplock_break(char *buffer,
                }
        }
        spin_unlock(&cifs_tcp_ses_lock);
@@ -48,6 +46,3 @@ index 44198b9a5315..19baeb4ca511 100644
  }
  
  void
--- 
-2.30.2
-

diff --git a/queue-4.4/series b/queue-4.4/series
index 11bb37cc3dc70523fcde6501311de64d61c9bf31..d5340976f75961674f1ad09a200216f3eb6c7eaf 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -5,3 +5,4 @@ x86-build-turn-off-fcf-protection-for-realmode-targe.patch
 ia64-mca-allocate-early-mca-with-gfp_atomic.patch
 cifs-revalidate-mapping-when-we-open-files-for-smb1-.patch
 cifs-silently-ignore-unknown-oplock-break-handle.patch
+bpf-x86-validate-computation-of-branch-displacements-for-x86-64.patch