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Jason Gunthorpe
31142a4ba6
RDMA/cm: Add min length checks to user structure copies
These are missing throughout ucma, it harmlessly copies garbage from userspace, but in this new code which uses min to compute the copy length it can result in uninitialized stack memory. Check for minimum length at the very start. BUG: KMSAN: uninit-value in ucma_connect+0x2aa/0xab0 drivers/infiniband/core/ucma.c:1091 CPU: 0 PID: 8457 Comm: syz-executor069 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1df/0x240 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 ucma_connect+0x2aa/0xab0 drivers/infiniband/core/ucma.c:1091 ucma_write+0x5c5/0x630 drivers/infiniband/core/ucma.c:1764 do_loop_readv_writev fs/read_write.c:737 [inline] do_iter_write+0x710/0xdc0 fs/read_write.c:1020 vfs_writev fs/read_write.c:1091 [inline] do_writev+0x42d/0x8f0 fs/read_write.c:1134 __do_sys_writev fs/read_write.c:1207 [inline] __se_sys_writev+0x9b/0xb0 fs/read_write.c:1204 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1204 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 34e2ab57a911 ("RDMA/ucma: Extend ucma_connect to receive ECE parameters") Fixes: 0cb15372a615 ("RDMA/cma: Connect ECE to rdma_accept") Link: https://lore.kernel.org/r/0-v1-d5b86dab17dc+28c25-ucma_syz_min_jgg@nvidia.com Reported-by: syzbot+086ab5ca9eafd2379aa6@syzkaller.appspotmail.com Reported-by: syzbot+7446526858b83c8828b2@syzkaller.appspotmail.com Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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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