From: Daniel Borkmann <dborkman@redhat.com>
Date: Fri, 28 Mar 2014 17:58:18 +0000 (+0100)
Subject: net: filter: add jited flag to indicate jit compiled filters
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f8bbbfc3b97f4c7a6c7c23185e520b22bfc3a21d;p=linux.git
net: filter: add jited flag to indicate jit compiled filters
This patch adds a jited flag into sk_filter struct in order to indicate
whether a filter is currently jited or not. The size of sk_filter is
not being expanded as the 32 bit 'len' member allows upper bits to be
reused since a filter can currently only grow as large as BPF_MAXINSNS.
Therefore, there's enough room also for other in future needed flags to
reuse 'len' field if necessary. The jited flag also allows for having
alternative interpreter functions running as currently, we can only
detect jit compiled filters by testing fp->bpf_func to not equal the
address of sk_run_filter().
Joint work with Alexei Starovoitov.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 7ddb9c83cdfc6..6f879c319a9db 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -925,6 +925,7 @@ void bpf_jit_compile(struct sk_filter *fp)
bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
fp->bpf_func = (void *)ctx.target;
+ fp->jited = 1;
out:
kfree(ctx.offsets);
return;
@@ -932,7 +933,7 @@ out:
void bpf_jit_free(struct sk_filter *fp)
{
- if (fp->bpf_func != sk_run_filter)
+ if (fp->jited)
module_free(NULL, fp->bpf_func);
kfree(fp);
}
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 4afad6c17d501..808ce1cae21ab 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -689,6 +689,7 @@ void bpf_jit_compile(struct sk_filter *fp)
((u64 *)image)[0] = (u64)code_base;
((u64 *)image)[1] = local_paca->kernel_toc;
fp->bpf_func = (void *)image;
+ fp->jited = 1;
}
out:
kfree(addrs);
@@ -697,7 +698,7 @@ out:
void bpf_jit_free(struct sk_filter *fp)
{
- if (fp->bpf_func != sk_run_filter)
+ if (fp->jited)
module_free(NULL, fp->bpf_func);
kfree(fp);
}
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 153f8f2cfd561..9c36dc398f907 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -877,6 +877,7 @@ void bpf_jit_compile(struct sk_filter *fp)
if (jit.start) {
set_memory_ro((unsigned long)header, header->pages);
fp->bpf_func = (void *) jit.start;
+ fp->jited = 1;
}
out:
kfree(addrs);
@@ -887,10 +888,12 @@ void bpf_jit_free(struct sk_filter *fp)
unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
struct bpf_binary_header *header = (void *)addr;
- if (fp->bpf_func == sk_run_filter)
+ if (!fp->jited)
goto free_filter;
+
set_memory_rw(addr, header->pages);
module_free(NULL, header);
+
free_filter:
kfree(fp);
}
diff --git a/arch/sparc/net/bpf_jit_comp.c b/arch/sparc/net/bpf_jit_comp.c
index d96d2a7c78eef..a82c6b2a9780c 100644
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -809,6 +809,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf];
if (image) {
bpf_flush_icache(image, image + proglen);
fp->bpf_func = (void *)image;
+ fp->jited = 1;
}
out:
kfree(addrs);
@@ -817,7 +818,7 @@ out:
void bpf_jit_free(struct sk_filter *fp)
{
- if (fp->bpf_func != sk_run_filter)
+ if (fp->jited)
module_free(NULL, fp->bpf_func);
kfree(fp);
}
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 293c57b74edcc..dc017735bb91b 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -772,6 +772,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
bpf_flush_icache(header, image + proglen);
set_memory_ro((unsigned long)header, header->pages);
fp->bpf_func = (void *)image;
+ fp->jited = 1;
}
out:
kfree(addrs);
@@ -791,7 +792,7 @@ static void bpf_jit_free_deferred(struct work_struct *work)
void bpf_jit_free(struct sk_filter *fp)
{
- if (fp->bpf_func != sk_run_filter) {
+ if (fp->jited) {
INIT_WORK(&fp->work, bpf_jit_free_deferred);
schedule_work(&fp->work);
} else {
diff --git a/include/linux/filter.h b/include/linux/filter.h
index e568c8ef896bf..e65e230873679 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -25,7 +25,8 @@ struct sock;
struct sk_filter
{
atomic_t refcnt;
- unsigned int len; /* Number of filter blocks */
+ u32 jited:1, /* Is our filter JIT'ed? */
+ len:31; /* Number of filter blocks */
struct rcu_head rcu;
unsigned int (*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter);
diff --git a/net/core/filter.c b/net/core/filter.c
index 65b75966e206a..bb3c76458ca9c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -646,6 +646,7 @@ static int __sk_prepare_filter(struct sk_filter *fp)
int err;
fp->bpf_func = sk_run_filter;
+ fp->jited = 0;
err = sk_chk_filter(fp->insns, fp->len);
if (err)