Eric Dumazet 2db344725e ppp: ensure minimum packet size in ppp_write() ... [ Upstream commit 44073187990d5629804ce0627525f6ea5cfef171 ] It seems pretty clear ppp layer assumed user space would always be kind to provide enough data in their write() to a ppp device. This patch makes sure user provides at least 2 bytes. It adds PPP_PROTO_LEN macro that could replace in net-next many occurrences of hard-coded 2 value. I replaced only one occurrence to ease backports to stable kernels. The bug manifests in the following report: BUG: KMSAN: uninit-value in ppp_send_frame+0x28d/0x27c0 drivers/net/ppp/ppp_generic.c:1740 ppp_send_frame+0x28d/0x27c0 drivers/net/ppp/ppp_generic.c:1740 __ppp_xmit_process+0x23e/0x4b0 drivers/net/ppp/ppp_generic.c:1640 ppp_xmit_process+0x1fe/0x480 drivers/net/ppp/ppp_generic.c:1661 ppp_write+0x5cb/0x5e0 drivers/net/ppp/ppp_generic.c:513 do_iter_write+0xb0c/0x1500 fs/read_write.c:853 vfs_writev fs/read_write.c:924 [inline] do_writev+0x645/0xe00 fs/read_write.c:967 __do_sys_writev fs/read_write.c:1040 [inline] __se_sys_writev fs/read_write.c:1037 [inline] __x64_sys_writev+0xe5/0x120 fs/read_write.c:1037 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was created at: slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:3251 [inline] __kmalloc_node_track_caller+0xe0c/0x1510 mm/slub.c:4974 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0x545/0xf90 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1126 [inline] ppp_write+0x11d/0x5e0 drivers/net/ppp/ppp_generic.c:501 do_iter_write+0xb0c/0x1500 fs/read_write.c:853 vfs_writev fs/read_write.c:924 [inline] do_writev+0x645/0xe00 fs/read_write.c:967 __do_sys_writev fs/read_write.c:1040 [inline] __se_sys_writev fs/read_write.c:1037 [inline] __x64_sys_writev+0xe5/0x120 fs/read_write.c:1037 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Paul Mackerras <paulus@samba.org> Cc: linux-ppp@vger.kernel.org Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-01-27 10:54:01 +01:00
..
bsd_comp.c
Kconfig
Makefile
ppp_async.c	tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer	2021-03-04 11:37:36 +01:00
ppp_deflate.c
ppp_generic.c	ppp: ensure minimum packet size in ppp_write()	2022-01-27 10:54:01 +01:00
ppp_mppe.c	mm, treewide: rename kzfree() to kfree_sensitive()	2020-08-07 11:33:22 -07:00
ppp_mppe.h
ppp_synctty.c	tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer	2021-03-04 11:37:36 +01:00
pppoe.c	net: make ->{get,set}sockopt in proto_ops optional	2020-07-19 18:16:41 -07:00
pppox.c
pptp.c	net: make ->{get,set}sockopt in proto_ops optional	2020-07-19 18:16:41 -07:00