Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2018-10-27

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Fix toctou race in BTF header validation, from Martin and Wenwen.

2) Fix devmap interface comparison in notifier call which was
   neglecting netns, from Taehee.

3) Several fixes in various places, for example, correcting direct
   packet access and helper function availability, from Daniel.

4) Fix BPF kselftest config fragment to include af_xdp and sockmap,
   from Naresh.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 3 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 7c7eeea8cffc..6377225b2082 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -365,10 +365,13 @@ void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
 }
 
 #ifdef CONFIG_BPF_JIT
+# define BPF_JIT_LIMIT_DEFAULT	(PAGE_SIZE * 40000)
+
 /* All BPF JIT sysctl knobs here. */
 int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);
 int bpf_jit_harden   __read_mostly;
 int bpf_jit_kallsyms __read_mostly;
+int bpf_jit_limit    __read_mostly = BPF_JIT_LIMIT_DEFAULT;
 
 static __always_inline void
 bpf_get_prog_addr_region(const struct bpf_prog *prog,
@@ -577,27 +580,64 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 	return ret;
 }
 
+static atomic_long_t bpf_jit_current;
+
+#if defined(MODULES_VADDR)
+static int __init bpf_jit_charge_init(void)
+{
+	/* Only used as heuristic here to derive limit. */
+	bpf_jit_limit = min_t(u64, round_up((MODULES_END - MODULES_VADDR) >> 2,
+					    PAGE_SIZE), INT_MAX);
+	return 0;
+}
+pure_initcall(bpf_jit_charge_init);
+#endif
+
+static int bpf_jit_charge_modmem(u32 pages)
+{
+	if (atomic_long_add_return(pages, &bpf_jit_current) >
+	    (bpf_jit_limit >> PAGE_SHIFT)) {
+		if (!capable(CAP_SYS_ADMIN)) {
+			atomic_long_sub(pages, &bpf_jit_current);
+			return -EPERM;
+		}
+	}
+
+	return 0;
+}
+
+static void bpf_jit_uncharge_modmem(u32 pages)
+{
+	atomic_long_sub(pages, &bpf_jit_current);
+}
+
 struct bpf_binary_header *
 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 		     unsigned int alignment,
 		     bpf_jit_fill_hole_t bpf_fill_ill_insns)
 {
 	struct bpf_binary_header *hdr;
-	unsigned int size, hole, start;
+	u32 size, hole, start, pages;
 
 	/* Most of BPF filters are really small, but if some of them
 	 * fill a page, allow at least 128 extra bytes to insert a
 	 * random section of illegal instructions.
 	 */
 	size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
+	pages = size / PAGE_SIZE;
+
+	if (bpf_jit_charge_modmem(pages))
+		return NULL;
 	hdr = module_alloc(size);
-	if (hdr == NULL)
+	if (!hdr) {
+		bpf_jit_uncharge_modmem(pages);
 		return NULL;
+	}
 
 	/* Fill space with illegal/arch-dep instructions. */
 	bpf_fill_ill_insns(hdr, size);
 
-	hdr->pages = size / PAGE_SIZE;
+	hdr->pages = pages;
 	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
 		     PAGE_SIZE - sizeof(*hdr));
 	start = (get_random_int() % hole) & ~(alignment - 1);
@@ -610,7 +650,10 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 
 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
 {
+	u32 pages = hdr->pages;
+
 	module_memfree(hdr);
+	bpf_jit_uncharge_modmem(pages);
 }
 
 /* This symbol is only overridden by archs that have different