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From: Aurelien Jarno <aurelien@aurel32.net>
To: libc-stable@sourceware.org
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Subject: [COMMITTED 2.33] aarch64: align stack in clone [BZ #27939]
Date: Wed, 26 Jan 2022 22:54:02 +0100	[thread overview]
Message-ID: <20220126215402.1392635-1-aurelien@aurel32.net> (raw)

From: Szabolcs Nagy <szabolcs.nagy@arm.com>

The AArch64 PCS requires 16 byte aligned stack.  Previously if the
caller passed an unaligned stack to clone then the child crashed.

Fixes bug 27939.

(cherry picked from commit 3842ba494963b1d76ad5f68b8d1e5c2279160e31)
---
 sysdeps/unix/sysv/linux/aarch64/clone.S | 2 ++
 1 file changed, 2 insertions(+)

This fixes a failure in the recently backported commit CVE-2021-3999
fix.

diff --git a/sysdeps/unix/sysv/linux/aarch64/clone.S b/sysdeps/unix/sysv/linux/aarch64/clone.S
index c9e63bae48..fe04bce6b6 100644
--- a/sysdeps/unix/sysv/linux/aarch64/clone.S
+++ b/sysdeps/unix/sysv/linux/aarch64/clone.S
@@ -47,6 +47,8 @@ ENTRY(__clone)
 	/* Sanity check args.  */
 	mov	x0, #-EINVAL
 	cbz	x10, .Lsyscall_error
+	/* Align sp.  */
+	and	x1, x1, -16
 	cbz	x1, .Lsyscall_error
 
 	/* Do the system call.  */
-- 
2.34.1


                 reply	other threads:[~2022-01-26 21:54 UTC|newest]

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