From: David Abdurachmanov <david.abdurachmanov@gmail.com> To: palmer@sifive.com, aou@eecs.berkeley.edu, keescook@chromium.org, luto@amacapital.net, wad@chromium.org, green.hu@gmail.com, deanbo422@gmail.com, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Cc: David Abdurachmanov <david.abdurachmanov@gmail.com> Subject: [PATCH 2/2] riscv: fix syscall_{get,set}_arguments Date: Thu, 6 Dec 2018 16:01:56 +0100 [thread overview] Message-ID: <20181206150156.28210-3-david.abdurachmanov@gmail.com> (raw) In-Reply-To: <20181206150156.28210-1-david.abdurachmanov@gmail.com> Testing with libseccomp master branch revealed that testcases with filters on syscall arguments were failing due to wrong values. Seccomp uses syscall_get_argumentsi() to copy syscall arguments, and there is a bug in pointer arithmetics in memcpy() call. Two alternative implementation were tested: the one in this patch and another one based on while-break loop. Both delivered the same results. This implementation is also used in arm, arm64 and nds32 arches. Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com> --- arch/riscv/include/asm/syscall.h | 42 ++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 10 deletions(-) diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h index bba3da6ef157..26ceb434a433 100644 --- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -70,19 +70,32 @@ static inline void syscall_set_return_value(struct task_struct *task, regs->a0 = (long) error ?: val; } +#define SYSCALL_MAX_ARGS 6 + static inline void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, unsigned int i, unsigned int n, unsigned long *args) { - BUG_ON(i + n > 6); + if (n == 0) + return; + + if (i + n > SYSCALL_MAX_ARGS) { + unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; + unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; + pr_warning("%s called with max args %d, handling only %d\n", + __func__, i + n, SYSCALL_MAX_ARGS); + memset(args_bad, 0, n_bad * sizeof(args[0])); + } + if (i == 0) { args[0] = regs->orig_a0; args++; i++; n--; } - memcpy(args, ®s->a1 + i * sizeof(regs->a1), n * sizeof(args[0])); + + memcpy(args, ®s->a0 + i, n * sizeof(args[0])); } static inline void syscall_set_arguments(struct task_struct *task, @@ -90,14 +103,23 @@ static inline void syscall_set_arguments(struct task_struct *task, unsigned int i, unsigned int n, const unsigned long *args) { - BUG_ON(i + n > 6); - if (i == 0) { - regs->orig_a0 = args[0]; - args++; - i++; - n--; - } - memcpy(®s->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0)); + if (n == 0) + return; + + if (i + n > SYSCALL_MAX_ARGS) { + pr_warning("%s called with max args %d, handling only %d\n", + __func__, i + n, SYSCALL_MAX_ARGS); + n = SYSCALL_MAX_ARGS - i; + } + + if (i == 0) { + regs->orig_a0 = args[0]; + args++; + i++; + n--; + } + + memcpy(®s->a0 + i, args, n * sizeof(args[0])); } static inline int syscall_get_arch(void) -- 2.19.2
WARNING: multiple messages have this Message-ID (diff)
From: David Abdurachmanov <david.abdurachmanov@gmail.com> To: palmer@sifive.com, aou@eecs.berkeley.edu, keescook@chromium.org, luto@amacapital.net, wad@chromium.org, green.hu@gmail.com, deanbo422@gmail.com, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Cc: David Abdurachmanov <david.abdurachmanov@gmail.com> Subject: [PATCH 2/2] riscv: fix syscall_{get,set}_arguments Date: Thu, 6 Dec 2018 16:01:56 +0100 [thread overview] Message-ID: <20181206150156.28210-3-david.abdurachmanov@gmail.com> (raw) In-Reply-To: <20181206150156.28210-1-david.abdurachmanov@gmail.com> Testing with libseccomp master branch revealed that testcases with filters on syscall arguments were failing due to wrong values. Seccomp uses syscall_get_argumentsi() to copy syscall arguments, and there is a bug in pointer arithmetics in memcpy() call. Two alternative implementation were tested: the one in this patch and another one based on while-break loop. Both delivered the same results. This implementation is also used in arm, arm64 and nds32 arches. Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com> --- arch/riscv/include/asm/syscall.h | 42 ++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 10 deletions(-) diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h index bba3da6ef157..26ceb434a433 100644 --- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -70,19 +70,32 @@ static inline void syscall_set_return_value(struct task_struct *task, regs->a0 = (long) error ?: val; } +#define SYSCALL_MAX_ARGS 6 + static inline void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, unsigned int i, unsigned int n, unsigned long *args) { - BUG_ON(i + n > 6); + if (n == 0) + return; + + if (i + n > SYSCALL_MAX_ARGS) { + unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; + unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; + pr_warning("%s called with max args %d, handling only %d\n", + __func__, i + n, SYSCALL_MAX_ARGS); + memset(args_bad, 0, n_bad * sizeof(args[0])); + } + if (i == 0) { args[0] = regs->orig_a0; args++; i++; n--; } - memcpy(args, ®s->a1 + i * sizeof(regs->a1), n * sizeof(args[0])); + + memcpy(args, ®s->a0 + i, n * sizeof(args[0])); } static inline void syscall_set_arguments(struct task_struct *task, @@ -90,14 +103,23 @@ static inline void syscall_set_arguments(struct task_struct *task, unsigned int i, unsigned int n, const unsigned long *args) { - BUG_ON(i + n > 6); - if (i == 0) { - regs->orig_a0 = args[0]; - args++; - i++; - n--; - } - memcpy(®s->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0)); + if (n == 0) + return; + + if (i + n > SYSCALL_MAX_ARGS) { + pr_warning("%s called with max args %d, handling only %d\n", + __func__, i + n, SYSCALL_MAX_ARGS); + n = SYSCALL_MAX_ARGS - i; + } + + if (i == 0) { + regs->orig_a0 = args[0]; + args++; + i++; + n--; + } + + memcpy(®s->a0 + i, args, n * sizeof(args[0])); } static inline int syscall_get_arch(void) -- 2.19.2 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2018-12-06 15:02 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-12-06 15:01 [PATCH 0/2] riscv: add support for SECCOMP and SECCOMP_FILTER David Abdurachmanov 2018-12-06 15:01 ` David Abdurachmanov 2018-12-06 15:01 ` [PATCH 1/2] riscv: add support for SECCOMP incl. filters David Abdurachmanov 2018-12-06 15:01 ` David Abdurachmanov 2018-12-06 16:47 ` Kees Cook 2018-12-06 16:47 ` Kees Cook 2018-12-06 17:10 ` David Abdurachmanov 2018-12-06 17:10 ` David Abdurachmanov 2018-12-06 16:51 ` Kees Cook 2018-12-06 16:51 ` Kees Cook 2018-12-06 17:11 ` David Abdurachmanov 2018-12-06 17:11 ` David Abdurachmanov 2018-12-06 18:25 ` David Abdurachmanov 2018-12-06 18:25 ` David Abdurachmanov 2018-12-06 18:32 ` Kees Cook 2018-12-06 18:32 ` Kees Cook 2018-12-06 17:06 ` Kees Cook 2018-12-06 17:06 ` Kees Cook 2018-12-06 17:12 ` David Abdurachmanov 2018-12-06 17:12 ` David Abdurachmanov 2018-12-06 15:01 ` David Abdurachmanov [this message] 2018-12-06 15:01 ` [PATCH 2/2] riscv: fix syscall_{get,set}_arguments David Abdurachmanov 2018-12-06 16:48 ` Kees Cook 2018-12-06 16:48 ` Kees Cook 2018-12-06 17:13 ` David Abdurachmanov 2018-12-06 17:13 ` David Abdurachmanov
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