Lokesh Dhoundiyal
9e6c6d17d1
ipv4: drop dst in multicast routing path
kmemleak reports the following when routing multicast traffic over an ipsec tunnel. Kmemleak output: unreferenced object 0x8000000044bebb00 (size 256): comm "softirq", pid 0, jiffies 4294985356 (age 126.810s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 80 00 00 00 05 13 74 80 ..............t. 80 00 00 00 04 9b bf f9 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f83947e0>] __kmalloc+0x1e8/0x300 [<00000000b7ed8dca>] metadata_dst_alloc+0x24/0x58 [<0000000081d32c20>] __ipgre_rcv+0x100/0x2b8 [<00000000824f6cf1>] gre_rcv+0x178/0x540 [<00000000ccd4e162>] gre_rcv+0x7c/0xd8 [<00000000c024b148>] ip_protocol_deliver_rcu+0x124/0x350 [<000000006a483377>] ip_local_deliver_finish+0x54/0x68 [<00000000d9271b3a>] ip_local_deliver+0x128/0x168 [<00000000bd4968ae>] xfrm_trans_reinject+0xb8/0xf8 [<0000000071672a19>] tasklet_action_common.isra.16+0xc4/0x1b0 [<0000000062e9c336>] __do_softirq+0x1fc/0x3e0 [<00000000013d7914>] irq_exit+0xc4/0xe0 [<00000000a4d73e90>] plat_irq_dispatch+0x7c/0x108 [<000000000751eb8e>] handle_int+0x16c/0x178 [<000000001668023b>] _raw_spin_unlock_irqrestore+0x1c/0x28 The metadata dst is leaked when ip_route_input_mc() updates the dst for the skb. Commit f38a9eb1f77b ("dst: Metadata destinations") correctly handled dropping the dst in ip_route_input_slow() but missed the multicast case which is handled by ip_route_input_mc(). Drop the dst in ip_route_input_mc() avoiding the leak. Fixes: f38a9eb1f77b ("dst: Metadata destinations") Signed-off-by: Lokesh Dhoundiyal <lokesh.dhoundiyal@alliedtelesis.co.nz> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220505020017.3111846-1-chris.packham@alliedtelesis.co.nz Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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