* [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes [not found] <160697103739.3146288.7437620795200799020.stgit@devnote2> @ 2020-12-04 15:04 ` tip-bot2 for Masami Hiramatsu 2020-12-05 0:12 ` Masami Hiramatsu 2020-12-06 9:09 ` tip-bot2 for Masami Hiramatsu 1 sibling, 1 reply; 6+ messages in thread From: tip-bot2 for Masami Hiramatsu @ 2020-12-04 15:04 UTC (permalink / raw) To: linux-tip-commits Cc: syzbot+9b64b619f10f19d19a7c, Masami Hiramatsu, Borislav Petkov, Srikar Dronamraju, stable, x86, linux-kernel 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@devnote2 --- 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); switch (attr) { case INAT_MAKE_PREFIX(INAT_PFX_ES): case INAT_MAKE_PREFIX(INAT_PFX_CS): @@ -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> struct insn_field { union { @@ -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 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes 2020-12-04 15:04 ` [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes tip-bot2 for Masami Hiramatsu @ 2020-12-05 0:12 ` Masami Hiramatsu 2020-12-05 10:17 ` Borislav Petkov 2020-12-09 18:05 ` Arnaldo Carvalho de Melo 0 siblings, 2 replies; 6+ messages in thread From: Masami Hiramatsu @ 2020-12-05 0:12 UTC (permalink / raw) To: linux-kernel Cc: tip-bot2 for Masami Hiramatsu, linux-tip-commits, syzbot+9b64b619f10f19d19a7c, Masami Hiramatsu, Borislav Petkov, Srikar Dronamraju, stable, x86 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@devnote2 > --- > 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); > switch (attr) { > case INAT_MAKE_PREFIX(INAT_PFX_ES): > case INAT_MAKE_PREFIX(INAT_PFX_CS): > @@ -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, -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes 2020-12-05 0:12 ` Masami Hiramatsu @ 2020-12-05 10:17 ` Borislav Petkov 2020-12-06 3:53 ` Masami Hiramatsu 2020-12-09 18:05 ` Arnaldo Carvalho de Melo 1 sibling, 1 reply; 6+ messages in thread From: Borislav Petkov @ 2020-12-05 10:17 UTC (permalink / raw) To: Masami Hiramatsu Cc: linux-kernel, tip-bot2 for Masami Hiramatsu, linux-tip-commits, syzbot+9b64b619f10f19d19a7c, Borislav Petkov, Srikar Dronamraju, stable, x86 On Sat, Dec 05, 2020 at 09:12:56AM +0900, Masami Hiramatsu wrote: > This may break tools/objtool build. Please keep "inat.h". How? Please elaborate. Build tests are fine here. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes 2020-12-05 10:17 ` Borislav Petkov @ 2020-12-06 3:53 ` Masami Hiramatsu 0 siblings, 0 replies; 6+ messages in thread From: Masami Hiramatsu @ 2020-12-06 3:53 UTC (permalink / raw) To: Borislav Petkov Cc: linux-kernel, tip-bot2 for Masami Hiramatsu, linux-tip-commits, syzbot+9b64b619f10f19d19a7c, Borislav Petkov, Srikar Dronamraju, stable, x86 On Sat, 5 Dec 2020 11:17:04 +0100 Borislav Petkov <bp@alien8.de> wrote: > On Sat, Dec 05, 2020 at 09:12:56AM +0900, Masami Hiramatsu wrote: > > This may break tools/objtool build. Please keep "inat.h". > > How? Please elaborate. > > Build tests are fine here. Oops, sorry, it was for perf build. Please refer commit 00a263902ac3 ("perf intel-pt: Use shared x86 insn decoder"). Thank you, -- Masami Hiramatsu <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes 2020-12-05 0:12 ` Masami Hiramatsu 2020-12-05 10:17 ` Borislav Petkov @ 2020-12-09 18:05 ` Arnaldo Carvalho de Melo 1 sibling, 0 replies; 6+ messages in thread From: Arnaldo Carvalho de Melo @ 2020-12-09 18:05 UTC (permalink / raw) To: Masami Hiramatsu Cc: linux-kernel, tip-bot2 for Masami Hiramatsu, linux-tip-commits, syzbot+9b64b619f10f19d19a7c, Borislav Petkov, Srikar Dronamraju, stable, x86 Em Sat, Dec 05, 2020 at 09:12:56AM +0900, Masami Hiramatsu escreveu: > 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@devnote2 > > --- > > 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); > > switch (attr) { > > case INAT_MAKE_PREFIX(INAT_PFX_ES): > > case INAT_MAKE_PREFIX(INAT_PFX_CS): > > @@ -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". And also it would be interesting to avoid updating both the kernel and the tools/ copy, otherwise one would have to test the tools build, which may break with such updates. The whole point of the copy is to avoid that, otherwise we could just use the kernel files directly. - Arnaldo ^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes [not found] <160697103739.3146288.7437620795200799020.stgit@devnote2> 2020-12-04 15:04 ` [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes tip-bot2 for Masami Hiramatsu @ 2020-12-06 9:09 ` tip-bot2 for Masami Hiramatsu 1 sibling, 0 replies; 6+ messages in thread From: tip-bot2 for Masami Hiramatsu @ 2020-12-06 9:09 UTC (permalink / raw) To: linux-tip-commits Cc: syzbot+9b64b619f10f19d19a7c, Masami Hiramatsu, Borislav Petkov, Srikar Dronamraju, stable, x86, linux-kernel The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 4e9a5ae8df5b3365183150f6df49e49dece80d8c Gitweb: https://git.kernel.org/tip/4e9a5ae8df5b3365183150f6df49e49dece80d8c Author: Masami Hiramatsu <mhiramat@kernel.org> AuthorDate: Thu, 03 Dec 2020 13:50:37 +09:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Sun, 06 Dec 2020 09:58:13 +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@devnote2 --- arch/x86/include/asm/insn.h | 15 +++++++++++++++ arch/x86/kernel/uprobes.c | 10 ++++++---- tools/arch/x86/include/asm/insn.h | 15 +++++++++++++++ 3 files changed, 36 insertions(+), 4 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); switch (attr) { case INAT_MAKE_PREFIX(INAT_PFX_ES): case INAT_MAKE_PREFIX(INAT_PFX_CS): @@ -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..52c6262 100644 --- a/tools/arch/x86/include/asm/insn.h +++ b/tools/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 ^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-12-09 18:05 UTC | newest]
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[not found] <160697103739.3146288.7437620795200799020.stgit@devnote2>
2020-12-04 15:04 ` [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes tip-bot2 for Masami Hiramatsu
2020-12-05 0:12 ` Masami Hiramatsu
2020-12-05 10:17 ` Borislav Petkov
2020-12-06 3:53 ` Masami Hiramatsu
2020-12-09 18:05 ` Arnaldo Carvalho de Melo
2020-12-06 9:09 ` tip-bot2 for Masami Hiramatsu
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