From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() 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 Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- lib/net_utils.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 lib/net_utils.c (limited to 'lib/net_utils.c') diff --git a/lib/net_utils.c b/lib/net_utils.c new file mode 100644 index 000000000..215cda672 --- /dev/null +++ b/lib/net_utils.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +bool mac_pton(const char *s, u8 *mac) +{ + int i; + + if (strnlen(s, MAC_ADDR_STR_LEN) < MAC_ADDR_STR_LEN) + return false; + + /* Don't dirty result unless string is valid MAC. */ + for (i = 0; i < ETH_ALEN; i++) { + if (!isxdigit(s[i * 3]) || !isxdigit(s[i * 3 + 1])) + return false; + if (i != ETH_ALEN - 1 && s[i * 3 + 2] != ':') + return false; + } + for (i = 0; i < ETH_ALEN; i++) { + mac[i] = (hex_to_bin(s[i * 3]) << 4) | hex_to_bin(s[i * 3 + 1]); + } + return true; +} +EXPORT_SYMBOL(mac_pton); -- cgit v1.3.1