From a9d48205d0aedda021fc3728972a9e9934c2b9de Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:26 -0700 Subject: [PATCH 1/6] net: fool proof dev_valid_name() We want to use dev_valid_name() to validate tunnel names, so better use strnlen(name, IFNAMSIZ) than strlen(name) to make sure to not upset KASAN. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 9b04a9fd1dfd..969462ebb296 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1027,7 +1027,7 @@ bool dev_valid_name(const char *name) { if (*name == '\0') return false; - if (strlen(name) >= IFNAMSIZ) + if (strnlen(name, IFNAMSIZ) == IFNAMSIZ) return false; if (!strcmp(name, ".") || !strcmp(name, "..")) return false; From 9cb726a212a82c88c98aa9f0037fd04777cd8fe5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:27 -0700 Subject: [PATCH 2/6] ip_tunnel: better validate user provided tunnel names Use dev_valid_name() to make sure user does not provide illegal device name. syzbot caught the following bug : BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline] BUG: KASAN: stack-out-of-bounds in __ip_tunnel_create+0xca/0x6b0 net/ipv4/ip_tunnel.c:257 Write of size 20 at addr ffff8801ac79f810 by task syzkaller268107/4482 CPU: 0 PID: 4482 Comm: syzkaller268107 Not tainted 4.16.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b9/0x29f lib/dump_stack.c:53 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 strlcpy include/linux/string.h:300 [inline] __ip_tunnel_create+0xca/0x6b0 net/ipv4/ip_tunnel.c:257 ip_tunnel_create net/ipv4/ip_tunnel.c:352 [inline] ip_tunnel_ioctl+0x818/0xd40 net/ipv4/ip_tunnel.c:861 ipip_tunnel_ioctl+0x1c5/0x420 net/ipv4/ipip.c:350 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525 sock_ioctl+0x47e/0x680 net/socket.c:1015 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 SYSC_ioctl fs/ioctl.c:708 [inline] SyS_ioctl+0x24/0x30 fs/ioctl.c:706 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/ipv4/ip_tunnel.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index de6d94482fe7..6b0e362cc99b 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -253,13 +253,14 @@ static struct net_device *__ip_tunnel_create(struct net *net, struct net_device *dev; char name[IFNAMSIZ]; - if (parms->name[0]) - strlcpy(name, parms->name, IFNAMSIZ); - else { - if (strlen(ops->kind) > (IFNAMSIZ - 3)) { - err = -E2BIG; + err = -E2BIG; + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + goto failed; + strlcpy(name, parms->name, IFNAMSIZ); + } else { + if (strlen(ops->kind) > (IFNAMSIZ - 3)) goto failed; - } strlcpy(name, ops->kind, IFNAMSIZ); strncat(name, "%d", 2); } From b95211e066fc3494b7c115060b2297b4ba21f025 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:28 -0700 Subject: [PATCH 3/6] ipv6: sit: better validate user provided tunnel names Use dev_valid_name() to make sure user does not provide illegal device name. syzbot caught the following bug : BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline] BUG: KASAN: stack-out-of-bounds in ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254 Write of size 33 at addr ffff8801b64076d8 by task syzkaller932654/4453 CPU: 0 PID: 4453 Comm: syzkaller932654 Not tainted 4.16.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b9/0x29f lib/dump_stack.c:53 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 strlcpy include/linux/string.h:300 [inline] ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254 ipip6_tunnel_ioctl+0xe71/0x241b net/ipv6/sit.c:1221 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525 sock_ioctl+0x47e/0x680 net/socket.c:1015 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 SYSC_ioctl fs/ioctl.c:708 [inline] SyS_ioctl+0x24/0x30 fs/ioctl.c:706 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/ipv6/sit.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 1522bcfd253f..2afce37a7177 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -250,11 +250,13 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net, if (!create) goto failed; - if (parms->name[0]) + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + goto failed; strlcpy(name, parms->name, IFNAMSIZ); - else + } else { strcpy(name, "sit%d"); - + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ipip6_tunnel_setup); if (!dev) From 5f42df013b8bc1b6511af7a04bf93b014884ae2a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:29 -0700 Subject: [PATCH 4/6] ip6_gre: better validate user provided tunnel names Use dev_valid_name() to make sure user does not provide illegal device name. syzbot caught the following bug : BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline] BUG: KASAN: stack-out-of-bounds in ip6gre_tunnel_locate+0x334/0x860 net/ipv6/ip6_gre.c:339 Write of size 20 at addr ffff8801afb9f7b8 by task syzkaller851048/4466 CPU: 1 PID: 4466 Comm: syzkaller851048 Not tainted 4.16.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b9/0x29f lib/dump_stack.c:53 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 strlcpy include/linux/string.h:300 [inline] ip6gre_tunnel_locate+0x334/0x860 net/ipv6/ip6_gre.c:339 ip6gre_tunnel_ioctl+0x69d/0x12e0 net/ipv6/ip6_gre.c:1195 dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334 dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525 sock_ioctl+0x47e/0x680 net/socket.c:1015 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 SYSC_ioctl fs/ioctl.c:708 [inline] SyS_ioctl+0x24/0x30 fs/ioctl.c:706 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: c12b395a4664 ("gre: Support GRE over IPv6") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index f8a103bdbd60..69727bc168cb 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -335,11 +335,13 @@ static struct ip6_tnl *ip6gre_tunnel_locate(struct net *net, if (t || !create) return t; - if (parms->name[0]) + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + return NULL; strlcpy(name, parms->name, IFNAMSIZ); - else + } else { strcpy(name, "ip6gre%d"); - + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ip6gre_tunnel_setup); if (!dev) From db7a65e3ab78e5b1c4b17c0870ebee35a4ee3257 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:30 -0700 Subject: [PATCH 5/6] ip6_tunnel: better validate user provided tunnel names Use valid_name() to make sure user does not provide illegal device name. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index df4c29f7d59f..da66aaac51ce 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -297,13 +297,16 @@ static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p) struct net_device *dev; struct ip6_tnl *t; char name[IFNAMSIZ]; - int err = -ENOMEM; + int err = -E2BIG; - if (p->name[0]) + if (p->name[0]) { + if (!dev_valid_name(p->name)) + goto failed; strlcpy(name, p->name, IFNAMSIZ); - else + } else { sprintf(name, "ip6tnl%%d"); - + } + err = -ENOMEM; dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ip6_tnl_dev_setup); if (!dev) From 537b361fbcbcc3cd6fe2bb47069fd292b9256d16 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2018 06:39:31 -0700 Subject: [PATCH 6/6] vti6: better validate user provided tunnel names Use valid_name() to make sure user does not provide illegal device name. Fixes: ed1efb2aefbb ("ipv6: Add support for IPsec virtual tunnel interfaces") Signed-off-by: Eric Dumazet Cc: Steffen Klassert Signed-off-by: David S. Miller --- net/ipv6/ip6_vti.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index 6ebb2e8777f4..c214ffec02f0 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -212,10 +212,13 @@ static struct ip6_tnl *vti6_tnl_create(struct net *net, struct __ip6_tnl_parm *p char name[IFNAMSIZ]; int err; - if (p->name[0]) + if (p->name[0]) { + if (!dev_valid_name(p->name)) + goto failed; strlcpy(name, p->name, IFNAMSIZ); - else + } else { sprintf(name, "ip6_vti%%d"); + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, vti6_dev_setup); if (!dev)