aboutsummaryrefslogtreecommitdiff
path: root/bl31
diff options
context:
space:
mode:
authorDouglas Raillard <douglas.raillard@arm.com>2017-02-24 18:14:15 +0000
committerdp-arm <dimitris.papastamos@arm.com>2017-03-31 13:58:48 +0100
commit51faada71a219a8b94cd8d8e423f0f22e9da4d8f (patch)
tree402ce88d1f332e3afda2a623a7ec66053deb2d24 /bl31
parente422f991df48306cd5d9629c4f1ed230b0807fdb (diff)
downloadtrusted-firmware-a-51faada71a219a8b94cd8d8e423f0f22e9da4d8f.tar.gz
Add support for GCC stack protection
Introduce new build option ENABLE_STACK_PROTECTOR. It enables compilation of all BL images with one of the GCC -fstack-protector-* options. A new platform function plat_get_stack_protector_canary() is introduced. It returns a value that is used to initialize the canary for stack corruption detection. Returning a random value will prevent an attacker from predicting the value and greatly increase the effectiveness of the protection. A message is printed at the ERROR level when a stack corruption is detected. To be effective, the global data must be stored at an address lower than the base of the stacks. Failure to do so would allow an attacker to overwrite the canary as part of an attack which would void the protection. FVP implementation of plat_get_stack_protector_canary is weak as there is no real source of entropy on the FVP. It therefore relies on a timer's value, which could be predictable. Change-Id: Icaaee96392733b721fa7c86a81d03660d3c1bc06 Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Diffstat (limited to 'bl31')
-rw-r--r--bl31/bl31.ld.S7
1 files changed, 6 insertions, 1 deletions
diff --git a/bl31/bl31.ld.S b/bl31/bl31.ld.S
index e5d6232e5d..3a3fbd9a71 100644
--- a/bl31/bl31.ld.S
+++ b/bl31/bl31.ld.S
@@ -140,7 +140,12 @@ SECTIONS
*/
__RW_START__ = . ;
- .data . : {
+ /*
+ * .data must be placed at a lower address than the stacks if the stack
+ * protector is enabled. Alternatively, the .data.stack_protector_canary
+ * section can be placed independently of the main .data section.
+ */
+ .data . : {
__DATA_START__ = .;
*(.data*)
__DATA_END__ = .;