use get_random_long for the per-task stack canary

PATCH In review Daniel Micay 5 participants 5 messages May 4, 2017 – May 5, 2017

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Stable branch MM core Scheduler exec and binfmt

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Daniel Micay

author

2017-05-04 13:32 UTC #0 lore raw

PATCH 1/1 use get_random_long for the per-task stack canary

The stack canary is an unsigned long and should be fully initialized to random data rather than only 32 bits of random data.

Cc [email protected]

Signed-off-by Daniel Micay <[email protected]>

---
 kernel/fork.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/fork.c +1 -1

index 56d85fd81411..ff84ff82f56a 100644
@@ -537,7 +537,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	set_task_stack_end_magic(tsk);
 
 #ifdef CONFIG_CC_STACKPROTECTOR
-	tsk->stack_canary = get_random_int();
+	tsk->stack_canary = get_random_long();
 #endif
 
 	/*

Signature · 1 line

2.12.2

Arjan van de Ven

2017-05-04 13:33 UTC #1 lore raw

Quoted 2 lines · Daniel Micay

The stack canary is an unsigned long and should be fully initialized to random data rather than only 32 bits of random data.

that makes sense to me... ack

Rik van Riel

Acked-by on v1 1/1

2017-05-04 14:04 UTC #2 lore raw

In reply to Daniel Micay

Quoted 7 lines · Daniel Micay

The stack canary is an unsigned long and should be fully initialized to
random data rather than only 32 bits of random data.
Cc [email protected]
Signed-off-by Daniel Micay <[email protected]>

Acked-by Rik van Riel <[email protected]>

Kees Cook

Acked-by

2017-05-04 14:29 UTC #3 lore raw

Quoted 9 lines · Rik van Riel

Quoted 7 lines · Daniel Micay
The stack canary is an unsigned long and should be fully initialized to
random data rather than only 32 bits of random data.
Cc [email protected]
Signed-off-by Daniel Micay <[email protected]>
Acked-by Rik van Riel <[email protected]>

Thanks! Ingo, should this go via tip?

Acked-by Kees Cook <[email protected]>

-Kees

Signature · 2 lines

Kees Cook
Pixel Security

tip-bot for Daniel Micay

merge bot

2017-05-05 08:18 UTC #4 lore raw

[tip:core/urgent] stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

In reply to Daniel Micay

stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

Commit-ID:  5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05
Gitweb:     http://git.kernel.org/tip/5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05
Author:     Daniel Micay <[email protected]>
AuthorDate: Thu, 4 May 2017 09:32:09 -0400
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 5 May 2017 08:05:13 +0200

stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

The stack canary is an 'unsigned long' and should be fully initialized to random data rather than only 32 bits of random data.

Signed-off-by Daniel Micay <[email protected]>

Acked-by Arjan van de Ven <[email protected]>

Acked-by Rik van Riel <[email protected]>

Acked-by Kees Cook <[email protected]>

Cc Arjan van Ven <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc [email protected]

Link http://lkml.kernel.org/r/[email protected] open here

Signed-off-by Ingo Molnar <[email protected]>

---
 kernel/fork.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/fork.c +1 -1

index 3a4343c..d681f8f 100644
@@ -536,7 +536,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	set_task_stack_end_magic(tsk);
 
 #ifdef CONFIG_CC_STACKPROTECTOR
-	tsk->stack_canary = get_random_int();
+	tsk->stack_canary = get_random_long();
 #endif
 
 	/*