Patch "bpf: fix check for attempt to corrupt spilled pointer" has been added to the 5.15-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    bpf: fix check for attempt to corrupt spilled pointer

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bpf-fix-check-for-attempt-to-corrupt-spilled-pointer.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 21766b76da85d5866779ada9b33661b230475e30
Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
Date:   Tue Dec 5 10:42:41 2023 -0800

    bpf: fix check for attempt to corrupt spilled pointer
    
    [ Upstream commit ab125ed3ec1c10ccc36bc98c7a4256ad114a3dae ]
    
    When register is spilled onto a stack as a 1/2/4-byte register, we set
    slot_type[BPF_REG_SIZE - 1] (plus potentially few more below it,
    depending on actual spill size). So to check if some stack slot has
    spilled register we need to consult slot_type[7], not slot_type[0].
    
    To avoid the need to remember and double-check this in the future, just
    use is_spilled_reg() helper.
    
    Fixes: 27113c59b6d0 ("bpf: Check the other end of slot_type for STACK_SPILL")
    Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20231205184248.1502704-4-andrii@xxxxxxxxxx
    Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 7318a5d44859..cc284371eea0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2844,7 +2844,7 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
 	 * so it's aligned access and [off, off + size) are within stack limits
 	 */
 	if (!env->allow_ptr_leaks &&
-	    state->stack[spi].slot_type[0] == STACK_SPILL &&
+	    is_spilled_reg(&state->stack[spi]) &&
 	    size != BPF_REG_SIZE) {
 		verbose(env, "attempt to corrupt spilled pointer on stack\n");
 		return -EACCES;




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux