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| author | Shivank Garg <shivankg@amd.com> | 2026-08-22 19:22:05 +0000 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2026-09-09 17:51:44 +0530 |
| commit | e873c74132f0c5f1452816cd9bb26208f0bba1e1 (patch) | |
| tree | cc1ce1567f5b982359331863ebd9da38741f8d2e /arch/arm/lib/putuser.S | |
| download | linux-stable-e873c74132f0c5f1452816cd9bb26208f0bba1e1.tar.gz linux-stable-e873c74132f0c5f1452816cd9bb26208f0bba1e1.zip | |
dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted
When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.
dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:
slab-use-after-free in dma_chan_put+0x3e6/0x4c0
Read of size 8 by task insmod/6319
Freed by task 6319:
kfree+0x225/0x470
dma_chan_put+0x395/0x4c0
dmaengine_put+0xf8/0x160
Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.
Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'arch/arm/lib/putuser.S')
| -rw-r--r-- | arch/arm/lib/putuser.S | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/arch/arm/lib/putuser.S b/arch/arm/lib/putuser.S new file mode 100644 index 000000000..bdd8836dc --- /dev/null +++ b/arch/arm/lib/putuser.S @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/arch/arm/lib/putuser.S + * + * Copyright (C) 2001 Russell King + * + * Idea from x86 version, (C) Copyright 1998 Linus Torvalds + * + * These functions have a non-standard call interface to make + * them more efficient, especially as they return an error + * value in addition to the "real" return value. + * + * __put_user_X + * + * Inputs: r0 contains the address + * r1 contains the address limit, which must be preserved + * r2, r3 contains the value + * Outputs: r0 is the error code + * lr corrupted + * + * No other registers must be altered. (see <asm/uaccess.h> + * for specific ASM register usage). + * + * Note that ADDR_LIMIT is either 0 or 0xc0000000 + * Note also that it is intended that __put_user_bad is not global. + */ +#include <linux/linkage.h> +#include <asm/assembler.h> +#include <asm/errno.h> +#include <asm/domain.h> + +ENTRY(__put_user_1) + check_uaccess r0, 1, r1, ip, __put_user_bad +1: TUSER(strb) r2, [r0] + mov r0, #0 + ret lr +ENDPROC(__put_user_1) + +ENTRY(__put_user_2) + check_uaccess r0, 2, r1, ip, __put_user_bad +#if __LINUX_ARM_ARCH__ >= 6 + +2: TUSER(strh) r2, [r0] + +#else + + mov ip, r2, lsr #8 +#ifndef __ARMEB__ +2: TUSER(strb) r2, [r0], #1 +3: TUSER(strb) ip, [r0] +#else +2: TUSER(strb) ip, [r0], #1 +3: TUSER(strb) r2, [r0] +#endif + +#endif /* __LINUX_ARM_ARCH__ >= 6 */ + mov r0, #0 + ret lr +ENDPROC(__put_user_2) + +ENTRY(__put_user_4) + check_uaccess r0, 4, r1, ip, __put_user_bad +4: TUSER(str) r2, [r0] + mov r0, #0 + ret lr +ENDPROC(__put_user_4) + +ENTRY(__put_user_8) + check_uaccess r0, 8, r1, ip, __put_user_bad +#ifdef CONFIG_THUMB2_KERNEL +5: TUSER(str) r2, [r0] +6: TUSER(str) r3, [r0, #4] +#else +5: TUSER(str) r2, [r0], #4 +6: TUSER(str) r3, [r0] +#endif + mov r0, #0 + ret lr +ENDPROC(__put_user_8) + +__put_user_bad: + mov r0, #-EFAULT + ret lr +ENDPROC(__put_user_bad) + +.pushsection __ex_table, "a" + .long 1b, __put_user_bad + .long 2b, __put_user_bad +#if __LINUX_ARM_ARCH__ < 6 + .long 3b, __put_user_bad +#endif + .long 4b, __put_user_bad + .long 5b, __put_user_bad + .long 6b, __put_user_bad +.popsection |