From 7d1982b4e335c1b184406b7566f6041bfe313c35 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 15 Jun 2018 02:30:47 +0200 Subject: bpf: fix panic in prog load calls cleanup While testing I found that when hitting error path in bpf_prog_load() where we jump to free_used_maps and prog contained BPF to BPF calls that were JITed earlier, then we never clean up the bpf_prog_kallsyms_add() done under jit_subprogs(). Add proper API to make BPF kallsyms deletion more clear and fix that. Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs") Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 45fc0f5000d8..297c56fa9cee 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -961,6 +961,9 @@ static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp) } #endif /* CONFIG_BPF_JIT */ +void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp); +void bpf_prog_kallsyms_del_all(struct bpf_prog *fp); + #define BPF_ANC BIT(15) static inline bool bpf_needs_clear_a(const struct sock_filter *first) -- cgit v1.2.3 From 9facc336876f7ecf9edba4c67b90426fde4ec898 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 15 Jun 2018 02:30:48 +0200 Subject: bpf: reject any prog that failed read-only lock We currently lock any JITed image as read-only via bpf_jit_binary_lock_ro() as well as the BPF image as read-only through bpf_prog_lock_ro(). In the case any of these would fail we throw a WARN_ON_ONCE() in order to yell loudly to the log. Perhaps, to some extend, this may be comparable to an allocation where __GFP_NOWARN is explicitly not set. Added via 65869a47f348 ("bpf: improve read-only handling"), this behavior is slightly different compared to any of the other in-kernel set_memory_ro() users who do not check the return code of set_memory_ro() and friends /at all/ (e.g. in the case of module_enable_ro() / module_disable_ro()). Given in BPF this is mandatory hardening step, we want to know whether there are any issues that would leave both BPF data writable. So it happens that syzkaller enabled fault injection and it triggered memory allocation failure deep inside x86's change_page_attr_set_clr() which was triggered from set_memory_ro(). Now, there are two options: i) leaving everything as is, and ii) reworking the image locking code in order to have a final checkpoint out of the central bpf_prog_select_runtime() which probes whether any of the calls during prog setup weren't successful, and then bailing out with an error. Option ii) is a better approach since this additional paranoia avoids altogether leaving any potential W+X pages from BPF side in the system. Therefore, lets be strict about it, and reject programs in such unlikely occasion. While testing I noticed also that one bpf_prog_lock_ro() call was missing on the outer dummy prog in case of calls, e.g. in the destructor we call bpf_prog_free_deferred() on the main prog where we try to bpf_prog_unlock_free() the program, and since we go via bpf_prog_select_runtime() do that as well. Reported-by: syzbot+3b889862e65a98317058@syzkaller.appspotmail.com Reported-by: syzbot+9e762b52dd17e616a7a5@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 60 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 22 deletions(-) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 297c56fa9cee..108f9812e196 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -469,7 +469,8 @@ struct sock_fprog_kern { }; struct bpf_binary_header { - unsigned int pages; + u16 pages; + u16 locked:1; u8 image[]; }; @@ -671,15 +672,18 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) -#ifdef CONFIG_ARCH_HAS_SET_MEMORY static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY fp->locked = 1; - WARN_ON_ONCE(set_memory_ro((unsigned long)fp, fp->pages)); + if (set_memory_ro((unsigned long)fp, fp->pages)) + fp->locked = 0; +#endif } static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY if (fp->locked) { WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages)); /* In case set_memory_rw() fails, we want to be the first @@ -687,34 +691,30 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) */ fp->locked = 0; } +#endif } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { - WARN_ON_ONCE(set_memory_ro((unsigned long)hdr, hdr->pages)); -} - -static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) -{ - WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages)); -} -#else -static inline void bpf_prog_lock_ro(struct bpf_prog *fp) -{ -} - -static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) -{ -} - -static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) -{ +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + hdr->locked = 1; + if (set_memory_ro((unsigned long)hdr, hdr->pages)) + hdr->locked = 0; +#endif } static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + if (hdr->locked) { + WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages)); + /* In case set_memory_rw() fails, we want to be the first + * to crash here instead of some random place later on. + */ + hdr->locked = 0; + } +#endif } -#endif /* CONFIG_ARCH_HAS_SET_MEMORY */ static inline struct bpf_binary_header * bpf_jit_binary_hdr(const struct bpf_prog *fp) @@ -725,6 +725,22 @@ bpf_jit_binary_hdr(const struct bpf_prog *fp) return (void *)addr; } +#ifdef CONFIG_ARCH_HAS_SET_MEMORY +static inline int bpf_prog_check_pages_ro_single(const struct bpf_prog *fp) +{ + if (!fp->locked) + return -ENOLCK; + if (fp->jited) { + const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); + + if (!hdr->locked) + return -ENOLCK; + } + + return 0; +} +#endif + int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap); static inline int sk_filter(struct sock *sk, struct sk_buff *skb) { -- cgit v1.2.3 From 6d5fc1957989266006db6ef3dfb9159b42cf0189 Mon Sep 17 00:00:00 2001 From: Toshiaki Makita Date: Thu, 14 Jun 2018 11:07:42 +0900 Subject: xdp: Fix handling of devmap in generic XDP Commit 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue") changed the return value type of __devmap_lookup_elem() from struct net_device * to struct bpf_dtab_netdev * but forgot to modify generic XDP code accordingly. Thus generic XDP incorrectly used struct bpf_dtab_netdev where struct net_device is expected, then skb->dev was set to invalid value. v2: - Fix compiler warning without CONFIG_BPF_SYSCALL. Fixes: 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue") Signed-off-by: Toshiaki Makita Acked-by: Yonghong Song Acked-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 12 ++++++++++++ include/linux/filter.h | 16 ++++++++++++++++ 2 files changed, 28 insertions(+) (limited to 'include/linux') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 995c3b1e59bf..7df32a3200f7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -488,12 +488,15 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth); /* Map specifics */ struct xdp_buff; +struct sk_buff; struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key); void __dev_map_insert_ctx(struct bpf_map *map, u32 index); void __dev_map_flush(struct bpf_map *map); int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, struct net_device *dev_rx); +int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, + struct bpf_prog *xdp_prog); struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key); void __cpu_map_insert_ctx(struct bpf_map *map, u32 index); @@ -586,6 +589,15 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, return 0; } +struct sk_buff; + +static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, + struct sk_buff *skb, + struct bpf_prog *xdp_prog) +{ + return 0; +} + static inline struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key) { diff --git a/include/linux/filter.h b/include/linux/filter.h index 108f9812e196..b615df57b7d5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -802,6 +803,21 @@ static inline bool bpf_dump_raw_ok(void) struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); +static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb, + struct net_device *fwd) +{ + unsigned int len; + + if (unlikely(!(fwd->flags & IFF_UP))) + return -ENETDOWN; + + len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN; + if (skb->len > len) + return -EMSGSIZE; + + return 0; +} + /* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the * same cpu context. Further for best results no more than a single map * for the do_redirect/do_flush pair should be used. This limitation is -- cgit v1.2.3 From 9bbe60a67be5a1c6f79b3c9be5003481a50529ff Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Sat, 16 Jun 2018 11:55:44 +0100 Subject: atm: Preserve value of skb->truesize when accounting to vcc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ATM accounts for in-flight TX packets in sk_wmem_alloc of the VCC on which they are to be sent. But it doesn't take ownership of those packets from the sock (if any) which originally owned them. They should remain owned by their actual sender until they've left the box. There's a hack in pskb_expand_head() to avoid adjusting skb->truesize for certain skbs, precisely to avoid messing up sk_wmem_alloc accounting. Ideally that hack would cover the ATM use case too, but it doesn't — skbs which aren't owned by any sock, for example PPP control frames, still get their truesize adjusted when the low-level ATM driver adds headroom. This has always been an issue, it seems. The truesize of a packet increases, and sk_wmem_alloc on the VCC goes negative. But this wasn't for normal traffic, only for control frames. So I think we just got away with it, and we probably needed to send 2GiB of LCP echo frames before the misaccounting would ever have caused a problem and caused atm_may_send() to start refusing packets. Commit 14afee4b609 ("net: convert sock.sk_wmem_alloc from atomic_t to refcount_t") did exactly what it was intended to do, and turned this mostly-theoretical problem into a real one, causing PPPoATM to fail immediately as sk_wmem_alloc underflows and atm_may_send() *immediately* starts refusing to allow new packets. The least intrusive solution to this problem is to stash the value of skb->truesize that was accounted to the VCC, in a new member of the ATM_SKB(skb) structure. Then in atm_pop_raw() subtract precisely that value instead of the then-current value of skb->truesize. Fixes: 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()") Signed-off-by: David Woodhouse Tested-by: Kevin Darbyshire-Bryant Signed-off-by: David S. Miller --- include/linux/atmdev.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux') diff --git a/include/linux/atmdev.h b/include/linux/atmdev.h index 0c27515d2cf6..8124815eb121 100644 --- a/include/linux/atmdev.h +++ b/include/linux/atmdev.h @@ -214,6 +214,7 @@ struct atmphy_ops { struct atm_skb_data { struct atm_vcc *vcc; /* ATM VCC */ unsigned long atm_options; /* ATM layer options */ + unsigned int acct_truesize; /* truesize accounted to vcc */ }; #define VCC_HTABLE_SIZE 32 @@ -241,6 +242,20 @@ void vcc_insert_socket(struct sock *sk); void atm_dev_release_vccs(struct atm_dev *dev); +static inline void atm_account_tx(struct atm_vcc *vcc, struct sk_buff *skb) +{ + /* + * Because ATM skbs may not belong to a sock (and we don't + * necessarily want to), skb->truesize may be adjusted, + * escaping the hack in pskb_expand_head() which avoids + * doing so for some cases. So stash the value of truesize + * at the time we accounted it, and atm_pop_raw() can use + * that value later, in case it changes. + */ + refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc); + ATM_SKB(skb)->acct_truesize = skb->truesize; + ATM_SKB(skb)->atm_options = vcc->atm_options; +} static inline void atm_force_charge(struct atm_vcc *vcc,int truesize) { -- cgit v1.2.3