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author | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2014-11-28 05:26:34 +0000 |
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committer | Kees Cook <keescook@google.com> | 2016-04-08 12:32:20 -0700 |
commit | 5e46412e971a9ceb0bb1471c8772a0da5ac91b1e (patch) | |
tree | 4dc5cb4f8860719336e9633567296a72b35a966f | |
parent | b878c96f83fd1bd45e0e1e61c9ac181b3afa5735 (diff) | |
download | qcom-msm-v3.10-5e46412e971a9ceb0bb1471c8772a0da5ac91b1e.tar.gz |
BACKPORT: arm64: ptrace: add NT_ARM_SYSTEM_CALL regset
This regeset is intended to be used to get and set a system call number
while tracing.
There was some discussion about possible approaches to do so:
(1) modify x8 register with ptrace(PTRACE_SETREGSET) indirectly,
and update regs->syscallno later on in syscall_trace_enter(), or
(2) define a dedicated regset for this purpose as on s390, or
(3) support ptrace(PTRACE_SET_SYSCALL) as on arch/arm
Thinking of the fact that user_pt_regs doesn't expose 'syscallno' to
tracer as well as that secure_computing() expects a changed syscall number,
especially case of -1, to be visible before this function returns in
syscall_trace_enter(), (1) doesn't work well.
We will take (2) since it looks much cleaner.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Bug: 28020023
Patchset: seccomp
(cherry picked from kernel/msm commit e2a1a6886c5c8f9dd90d3ab57403acc00443e160)
Signed-off-by: Kees Cook <keescook@google.com>
Change-Id: Ibcd388caea1becc004248dcc539e0824f217f757
-rw-r--r-- | arch/arm64/kernel/ptrace.c | 35 | ||||
-rw-r--r-- | include/uapi/linux/elf.h | 1 |
2 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 161e41ce46b..070df4c42d4 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -549,6 +549,32 @@ static int tls_set(struct task_struct *target, const struct user_regset *regset, return ret; } +static int system_call_get(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + void *kbuf, void __user *ubuf) +{ + int syscallno = task_pt_regs(target)->syscallno; + + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, + &syscallno, 0, -1); +} + +static int system_call_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int syscallno, ret; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1); + if (ret) + return ret; + + task_pt_regs(target)->syscallno = syscallno; + return ret; +} + enum aarch64_regset { REGSET_GPR, REGSET_FPR, @@ -557,6 +583,7 @@ enum aarch64_regset { REGSET_HW_BREAK, REGSET_HW_WATCH, #endif + REGSET_SYSTEM_CALL, }; static const struct user_regset aarch64_regsets[] = { @@ -606,6 +633,14 @@ static const struct user_regset aarch64_regsets[] = { .set = hw_break_set, }, #endif + [REGSET_SYSTEM_CALL] = { + .core_note_type = NT_ARM_SYSTEM_CALL, + .n = 1, + .size = sizeof(int), + .align = sizeof(int), + .get = system_call_get, + .set = system_call_set, + }, }; static const struct user_regset_view user_aarch64_view = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index ef6103bf1f9..80c61675815 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -395,6 +395,7 @@ typedef struct elf64_shdr { #define NT_ARM_TLS 0x401 /* ARM TLS register */ #define NT_ARM_HW_BREAK 0x402 /* ARM hardware breakpoint registers */ #define NT_ARM_HW_WATCH 0x403 /* ARM hardware watchpoint registers */ +#define NT_ARM_SYSTEM_CALL 0x404 /* ARM system call number */ #define NT_METAG_CBUF 0x500 /* Metag catch buffer registers */ #define NT_METAG_RPIPE 0x501 /* Metag read pipeline state */ #define NT_METAG_TLS 0x502 /* Metag TLS pointer */ |