On Fri, 04 Dec 2020 15:04:03 -0000 "tip-bot2 for Masami Hiramatsu" tip-bot2@linutronix.de wrote:
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 9dc23f960adb9ce410ef835b32a2398fdb09c828 Gitweb: https://git.kernel.org/tip/9dc23f960adb9ce410ef835b32a2398fdb09c828 Author: Masami Hiramatsu mhiramat@kernel.org AuthorDate: Thu, 03 Dec 2020 13:50:37 +09:00 Committer: Borislav Petkov bp@suse.de CommitterDate: Fri, 04 Dec 2020 14:32:57 +01:00
x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes
Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be
insn.prefixes.bytes[i] != 0 and i < 4
instead of using insn.prefixes.nbytes.
Introduce a for_each_insn_prefix() macro for this purpose. Debugged by Kees Cook keescook@chromium.org.
[ bp: Massage commit message, sync with the respective header in tools/ and drop "we". ]
Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Srikar Dronamraju srikar@linux.vnet.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@dev...
arch/x86/include/asm/insn.h | 15 +++++++++++++++ arch/x86/kernel/uprobes.c | 10 ++++++---- tools/arch/x86/include/asm/insn.h | 17 ++++++++++++++++- 3 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h index 5c1ae3e..a8c3d28 100644 --- a/arch/x86/include/asm/insn.h +++ b/arch/x86/include/asm/insn.h @@ -201,6 +201,21 @@ static inline int insn_offset_immediate(struct insn *insn) return insn_offset_displacement(insn) + insn->displacement.nbytes; } +/**
- for_each_insn_prefix() -- Iterate prefixes in the instruction
- @insn: Pointer to struct insn.
- @idx: Index storage.
- @prefix: Prefix byte.
- Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
- and the index is stored in @idx (note that this @idx is just for a cursor,
- do not change it.)
- Since prefixes.nbytes can be bigger than 4 if some prefixes
- are repeated, it cannot be used for looping over the prefixes.
- */
+#define for_each_insn_prefix(insn, idx, prefix) \
- for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++)
#define POP_SS_OPCODE 0x1f #define MOV_SREG_OPCODE 0x8e diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 3fdaa04..138bdb1 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -255,12 +255,13 @@ static volatile u32 good_2byte_insns[256 / 32] = { static bool is_prefix_bad(struct insn *insn) {
- insn_byte_t p; int i;
- for (i = 0; i < insn->prefixes.nbytes; i++) {
- for_each_insn_prefix(insn, i, p) { insn_attr_t attr;
attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]);
attr = inat_get_opcode_attribute(p);@@ -715,6 +716,7 @@ static const struct uprobe_xol_ops push_xol_ops = { static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) { u8 opc1 = OPCODE1(insn);
- insn_byte_t p; int i;
switch (opc1) { @@ -746,8 +748,8 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix. * No one uses these insns, reject any branch insns with such prefix. */
- for (i = 0; i < insn->prefixes.nbytes; i++) {
if (insn->prefixes.bytes[i] == 0x66)
- for_each_insn_prefix(insn, i, p) {
if (p == 0x66) return -ENOTSUPP;diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h index 568854b..a8c3d28 100644 --- a/tools/arch/x86/include/asm/insn.h +++ b/tools/arch/x86/include/asm/insn.h @@ -8,7 +8,7 @@ */ /* insn_attr_t is defined in inat.h */ -#include "inat.h" +#include <asm/inat.h>
This may break tools/objtool build. Please keep "inat.h".
Thank you,