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Date: Tue, 25 Mar 2014 13:10:49 +0100
From: Daniel Borkmann <dborkman@...hat.com>
To: davem@...emloft.net
Cc: ast@...mgrid.com, netdev@...r.kernel.org,
Pablo Neira Ayuso <pablo@...filter.org>
Subject: [PATCH net-next v2 1/9] 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@...mgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@...hat.com>
Cc: Pablo Neira Ayuso <pablo@...filter.org>
---
arch/arm/net/bpf_jit_32.c | 3 ++-
arch/powerpc/net/bpf_jit_comp.c | 3 ++-
arch/s390/net/bpf_jit_comp.c | 5 ++++-
arch/sparc/net/bpf_jit_comp.c | 3 ++-
arch/x86/net/bpf_jit_comp.c | 3 ++-
include/linux/filter.h | 3 ++-
net/core/filter.c | 1 +
7 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 271b5e9..e72ff51 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 555034f..c0c5fcb 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 708d60e..dd2d9b3 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 01fe994..8c01be6 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 4ed75dd..7fa182c 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 e568c8e..e65e230 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 ad30d62..2874cc8 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)
--
1.7.11.7
--
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