@@ -41,7 +41,7 @@ find_section(struct bdb_header *bdb, int section_id)
{
u8 *base = (u8 *)bdb;
int index = 0;
- u16 total, current_size;
+ u32 total, current_size;
u8 current_id;
/* skip to first section */
@@ -56,6 +56,10 @@ find_section(struct bdb_header *bdb, int section_id)
current_size = *((u16 *)(base + index));
index += 2;
+ /* The MIPI Sequence Block v3+ has a separate size field. */
+ if (current_id == BDB_MIPI_SEQUENCE && *(base + index) >= 3)
+ current_size = *((const u32 *)(base + index + 1));
+
if (index + current_size > total)
return NULL;
@@ -794,6 +798,12 @@ parse_mipi(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
return;
}
+ /* Fail gracefully for forward incompatible sequence block. */
+ if (sequence->version >= 3) {
+ DRM_ERROR("Unable to parse MIPI Sequence Block v3+\n");
+ return;
+ }
+
DRM_DEBUG_DRIVER("Found MIPI sequence block\n");
block_size = get_blocksize(sequence);
This is a note to let you know that I have just added a patch titled drm/i915/bios: handle MIPI Sequence Block v3+ gracefully to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.19.8-ckt9. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 5d0e26fb7d9e84d6e676889134a79c9bd5ab4191 Mon Sep 17 00:00:00 2001 From: Jani Nikula <jani.nikula@intel.com> Date: Thu, 17 Sep 2015 16:42:07 +0300 Subject: drm/i915/bios: handle MIPI Sequence Block v3+ gracefully commit cd67d226ebd909d239d2c6e5a6abd6e2a338d1cd upstream. The VBT MIPI Sequence Block version 3 has forward incompatible changes: First, the block size in the header has been specified reserved, and the actual size is a separate 32-bit value within the block. The current find_section() function to will only look at the size in the block header, and, depending on what's in that now reserved size field, continue looking for other sections in the wrong place. Fix this by taking the new block size field into account. This will ensure that the lookups for other sections will work properly, as long as the new 32-bit size does not go beyond the opregion VBT mailbox size. Second, the contents of the block have been completely changed. Gracefully refuse parsing the yet unknown data version. Cc: Deepak M <m.deepak@intel.com> Reviewed-by: Deepak M <m.deepak@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/gpu/drm/i915/intel_bios.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) -- 1.9.1