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authorAlexei Starovoitov <ast@plumgrid.com>2015-04-27 14:40:37 -0700
committerDavid S. Miller <davem@davemloft.net>2015-04-27 23:11:49 -0400
commit876a7ae65b86d8cec8efe7d15d050ac61116874e (patch)
tree6458c36e3f2c0cd2f2ca7c1dfcee6fc5b9c7dd19 /kernel
parentnet: netcp: remove call to netif_carrier_(on/off) for MAC to Phy interface (diff)
downloadlinux-dev-876a7ae65b86d8cec8efe7d15d050ac61116874e.tar.xz
linux-dev-876a7ae65b86d8cec8efe7d15d050ac61116874e.zip
bpf: fix 64-bit divide
ALU64_DIV instruction should be dividing 64-bit by 64-bit, whereas do_div() does 64-bit by 32-bit divide. x64 and arm64 JITs correctly implement 64 by 64 unsigned divide. llvm BPF backend emits code assuming that ALU64_DIV does 64 by 64. Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets") Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/core.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 4139a0f8b558..54f0e7fcd0e2 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -357,8 +357,8 @@ select_insn:
ALU64_MOD_X:
if (unlikely(SRC == 0))
return 0;
- tmp = DST;
- DST = do_div(tmp, SRC);
+ div64_u64_rem(DST, SRC, &tmp);
+ DST = tmp;
CONT;
ALU_MOD_X:
if (unlikely(SRC == 0))
@@ -367,8 +367,8 @@ select_insn:
DST = do_div(tmp, (u32) SRC);
CONT;
ALU64_MOD_K:
- tmp = DST;
- DST = do_div(tmp, IMM);
+ div64_u64_rem(DST, IMM, &tmp);
+ DST = tmp;
CONT;
ALU_MOD_K:
tmp = (u32) DST;
@@ -377,7 +377,7 @@ select_insn:
ALU64_DIV_X:
if (unlikely(SRC == 0))
return 0;
- do_div(DST, SRC);
+ DST = div64_u64(DST, SRC);
CONT;
ALU_DIV_X:
if (unlikely(SRC == 0))
@@ -387,7 +387,7 @@ select_insn:
DST = (u32) tmp;
CONT;
ALU64_DIV_K:
- do_div(DST, IMM);
+ DST = div64_u64(DST, IMM);
CONT;
ALU_DIV_K:
tmp = (u32) DST;