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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3c1532df5c
In ftrace_syscall_enter(),
syscall_get_arguments(..., 0, n, ...)
if (i == 0) { <handle ORIG_r0> ...; n--;}
memcpy(..., n * sizeof(args[0]));
If 'number of arguments(n)' is zero and 'argument index(i)' is also zero in
syscall_get_arguments(), none of arguments should be copied by memcpy().
Otherwise 'n--' can be a big positive number and unexpected amount of data
will be copied. Tracing system calls which take no argument, say sync(void),
may hit this case and eventually make the system corrupted.
This patch fixes the issue both in syscall_get_arguments() and
syscall_set_arguments().
Cc: <stable@vger.kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
114 lines
2.5 KiB
C
114 lines
2.5 KiB
C
/*
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* Access to user system call parameters and results
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*
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* See asm-generic/syscall.h for descriptions of what we must do here.
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*/
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#ifndef _ASM_ARM_SYSCALL_H
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#define _ASM_ARM_SYSCALL_H
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#include <linux/audit.h> /* for AUDIT_ARCH_* */
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#include <linux/elf.h> /* for ELF_EM */
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <asm/unistd.h>
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#define NR_syscalls (__NR_syscalls)
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extern const unsigned long sys_call_table[];
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static inline int syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return task_thread_info(task)->syscall;
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}
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static inline void syscall_rollback(struct task_struct *task,
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struct pt_regs *regs)
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{
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regs->ARM_r0 = regs->ARM_ORIG_r0;
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}
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static inline long syscall_get_error(struct task_struct *task,
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struct pt_regs *regs)
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{
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unsigned long error = regs->ARM_r0;
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return IS_ERR_VALUE(error) ? error : 0;
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}
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static inline long syscall_get_return_value(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->ARM_r0;
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}
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static inline void syscall_set_return_value(struct task_struct *task,
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struct pt_regs *regs,
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int error, long val)
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{
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regs->ARM_r0 = (long) error ? error : val;
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}
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#define SYSCALL_MAX_ARGS 7
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static inline void syscall_get_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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unsigned long *args)
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{
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if (n == 0)
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return;
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if (i + n > SYSCALL_MAX_ARGS) {
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unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
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unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
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pr_warning("%s called with max args %d, handling only %d\n",
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__func__, i + n, SYSCALL_MAX_ARGS);
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memset(args_bad, 0, n_bad * sizeof(args[0]));
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n = SYSCALL_MAX_ARGS - i;
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}
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if (i == 0) {
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args[0] = regs->ARM_ORIG_r0;
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args++;
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i++;
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n--;
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}
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memcpy(args, ®s->ARM_r0 + i, n * sizeof(args[0]));
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}
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static inline void syscall_set_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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const unsigned long *args)
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{
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if (n == 0)
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return;
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if (i + n > SYSCALL_MAX_ARGS) {
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pr_warning("%s called with max args %d, handling only %d\n",
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__func__, i + n, SYSCALL_MAX_ARGS);
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n = SYSCALL_MAX_ARGS - i;
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}
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if (i == 0) {
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regs->ARM_ORIG_r0 = args[0];
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args++;
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i++;
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n--;
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}
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memcpy(®s->ARM_r0 + i, args, n * sizeof(args[0]));
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}
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static inline int syscall_get_arch(struct task_struct *task,
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struct pt_regs *regs)
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{
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/* ARM tasks don't change audit architectures on the fly. */
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return AUDIT_ARCH_ARM;
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}
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#endif /* _ASM_ARM_SYSCALL_H */
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