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[AUDIT] Don't allow ptrace to fool auditing, log arch of audited syscalls.

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We were calling ptrace_notify() after auditing the syscall and arguments,
but the debugger could have _changed_ them before the syscall was actually
invoked. Reorder the calls to fix that.

While we're touching ever call to audit_syscall_entry(), we also make it
take an extra argument: the architecture of the syscall which was made,
because some architectures allow more than one type of syscall.

Also add an explicit success/failure flag to audit_syscall_exit(), for
the benefit of architectures which return that in a condition register
rather than only returning a single register.

Change type of syscall return value to 'long' not 'int'.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
2005-04-29 16:08:28 +01:00
parent ea3834d9fb
commit 2fd6f58ba6
8 changed files with 146 additions and 65 deletions
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19
arch/i386/kernel/ptrace.c
View File

@ -682,24 +682,18 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit)
/* do the secure computing check first */
secure_computing(regs->orig_eax);
if (unlikely(current->audit_context)) {
if (!entryexit)
audit_syscall_entry(current, regs->orig_eax,
regs->ebx, regs->ecx,
regs->edx, regs->esi);
else
audit_syscall_exit(current, regs->eax);
}
if (unlikely(current->audit_context) && entryexit)
audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
if (!(current->ptrace & PT_PTRACED))
return;
goto out;
/* Fake a debug trap */
if (test_thread_flag(TIF_SINGLESTEP))
send_sigtrap(current, regs, 0);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
goto out;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
@ -714,4 +708,9 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit)
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(current, AUDIT_ARCH_I386, regs->orig_eax,
regs->ebx, regs->ecx, regs->edx, regs->esi);
}

31
arch/ia64/kernel/ptrace.c
View File

@ -1595,20 +1595,25 @@ syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
long arg4, long arg5, long arg6, long arg7,
struct pt_regs regs)
{
long syscall;
if (unlikely(current->audit_context)) {
if (IS_IA32_PROCESS(&regs))
syscall = regs.r1;
else
syscall = regs.r15;
audit_syscall_entry(current, syscall, arg0, arg1, arg2, arg3);
}
if (test_thread_flag(TIF_SYSCALL_TRACE)
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
syscall_trace();
if (unlikely(current->audit_context)) {
long syscall;
int arch;
if (IS_IA32_PROCESS(&regs)) {
syscall = regs.r1;
arch = AUDIT_ARCH_I386;
} else {
syscall = regs.r15;
arch = AUDIT_ARCH_IA64;
}
audit_syscall_entry(current, arch, syscall, arg0, arg1, arg2, arg3);
}
}
/* "asmlinkage" so the input arguments are preserved... */
@ -1619,7 +1624,7 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
struct pt_regs regs)
{
if (unlikely(current->audit_context))
audit_syscall_exit(current, regs.r8);
audit_syscall_exit(current, AUDITSC_RESULT(regs.r10), regs.r8);
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))

38
arch/mips/kernel/ptrace.c
View File

@ -300,25 +300,38 @@ out:
return ret;
}
static inline int audit_arch()
{
#ifdef CONFIG_CPU_LITTLE_ENDIAN
#ifdef CONFIG_MIPS64
if (!(current->thread.mflags & MF_32BIT_REGS))
return AUDIT_ARCH_MIPSEL64;
#endif /* MIPS64 */
return AUDIT_ARCH_MIPSEL;
#else /* big endian... */
#ifdef CONFIG_MIPS64
if (!(current->thread.mflags & MF_32BIT_REGS))
return AUDIT_ARCH_MIPS64;
#endif /* MIPS64 */
return AUDIT_ARCH_MIPS;
#endif /* endian */
}
/*
* Notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
{
if (unlikely(current->audit_context)) {
if (!entryexit)
audit_syscall_entry(current, regs->regs[2],
regs->regs[4], regs->regs[5],
regs->regs[6], regs->regs[7]);
else
audit_syscall_exit(current, regs->regs[2]);
}
if (unlikely(current->audit_context) && entryexit)
audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]), regs->regs[2]);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
goto out;
if (!(current->ptrace & PT_PTRACED))
return;
goto out;
/* The 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
@ -334,4 +347,9 @@ asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(current, audit_arch(), regs->regs[2],
regs->regs[4], regs->regs[5],
regs->regs[6], regs->regs[7]);
}

17
arch/ppc64/kernel/ptrace.c
View File

@ -304,14 +304,17 @@ static void do_syscall_trace(void)
void do_syscall_trace_enter(struct pt_regs *regs)
{
if (unlikely(current->audit_context))
audit_syscall_entry(current, regs->gpr[0],
regs->gpr[3], regs->gpr[4],
regs->gpr[5], regs->gpr[6]);
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
if (unlikely(current->audit_context))
audit_syscall_entry(current,
test_thread_flag(TIF_32BIT)?AUDIT_ARCH_PPC:AUDIT_ARCH_PPC64,
regs->gpr[0],
regs->gpr[3], regs->gpr[4],
regs->gpr[5], regs->gpr[6]);
}
void do_syscall_trace_leave(struct pt_regs *regs)
@ -319,7 +322,9 @@ void do_syscall_trace_leave(struct pt_regs *regs)
secure_computing(regs->gpr[0]);
if (unlikely(current->audit_context))
audit_syscall_exit(current, regs->result);
audit_syscall_exit(current,
(regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
regs->result);
if ((test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SINGLESTEP))

21
arch/s390/kernel/ptrace.c
View File

@ -711,18 +711,13 @@ out:
asmlinkage void
syscall_trace(struct pt_regs *regs, int entryexit)
{
if (unlikely(current->audit_context)) {
if (!entryexit)
audit_syscall_entry(current, regs->gprs[2],
regs->orig_gpr2, regs->gprs[3],
regs->gprs[4], regs->gprs[5]);
else
audit_syscall_exit(current, regs->gprs[2]);
}
if (unlikely(current->audit_context) && entryexit)
audit_syscall_exit(current, AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
goto out;
if (!(current->ptrace & PT_PTRACED))
return;
goto out;
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
@ -735,4 +730,10 @@ syscall_trace(struct pt_regs *regs, int entryexit)
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(current,
test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
regs->gprs[4], regs->gprs[5]);
}

15
arch/x86_64/kernel/ptrace.c
View File

@ -629,25 +629,28 @@ static void syscall_trace(struct pt_regs *regs)
}
}
#define audit_arch() (test_thread_flag(TIF_IA32) ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64)
asmlinkage void syscall_trace_enter(struct pt_regs *regs)
{
/* do the secure computing check first */
secure_computing(regs->orig_rax);
if (unlikely(current->audit_context))
audit_syscall_entry(current, regs->orig_rax,
regs->rdi, regs->rsi,
regs->rdx, regs->r10);
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
syscall_trace(regs);
if (unlikely(current->audit_context))
audit_syscall_entry(current, audit_arch(), regs->orig_rax,
regs->rdi, regs->rsi,
regs->rdx, regs->r10);
}
asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
if (unlikely(current->audit_context))
audit_syscall_exit(current, regs->rax);
audit_syscall_exit(current, AUDITSC_RESULT(regs->rax), regs->rax);
if ((test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SINGLESTEP))

48
include/linux/audit.h
View File

@ -24,6 +24,9 @@
#ifndef _LINUX_AUDIT_H_
#define _LINUX_AUDIT_H_
#include <linux/sched.h>
#include <linux/elf.h>
/* Request and reply types */
#define AUDIT_GET 1000 /* Get status */
#define AUDIT_SET 1001 /* Set status (enable/disable/auditd) */
@ -67,6 +70,7 @@
#define AUDIT_FSGID 8
#define AUDIT_LOGINUID 9
#define AUDIT_PERS 10
#define AUDIT_ARCH 11
/* These are ONLY useful when checking
* at syscall exit time (AUDIT_AT_EXIT). */
@ -96,6 +100,38 @@
#define AUDIT_FAIL_PRINTK 1
#define AUDIT_FAIL_PANIC 2
/* distinguish syscall tables */
#define __AUDIT_ARCH_64BIT 0x80000000
#define __AUDIT_ARCH_LE 0x40000000
#define AUDIT_ARCH_ALPHA (EM_ALPHA|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_ARM (EM_ARM|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_ARMEB (EM_ARM)
#define AUDIT_ARCH_CRIS (EM_CRIS|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_FRV (EM_FRV)
#define AUDIT_ARCH_H8300 (EM_H8_300)
#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_IA64 (EM_IA_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_M32R (EM_M32R)
#define AUDIT_ARCH_M68K (EM_68K)
#define AUDIT_ARCH_MIPS (EM_MIPS)
#define AUDIT_ARCH_MIPSEL (EM_MIPS|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_MIPS64 (EM_MIPS|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_MIPSEL64 (EM_MIPS|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_PARISC (EM_PARISC)
#define AUDIT_ARCH_PARISC64 (EM_PARISC|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_PPC (EM_PPC)
#define AUDIT_ARCH_PPC64 (EM_PPC64|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_S390 (EM_S390)
#define AUDIT_ARCH_S390X (EM_S390|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_SH (EM_SH)
#define AUDIT_ARCH_SHEL (EM_SH|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_SH64 (EM_SH|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_SHEL64 (EM_SH|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_SPARC (EM_SPARC)
#define AUDIT_ARCH_SPARC64 (EM_SPARC64|__AUDIT_ARCH_64BIT)
#define AUDIT_ARCH_V850 (EM_V850|__AUDIT_ARCH_LE)
#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
#ifndef __KERNEL__
struct audit_message {
struct nlmsghdr nlh;
@ -129,15 +165,19 @@ struct audit_buffer;
struct audit_context;
struct inode;
#define AUDITSC_INVALID 0
#define AUDITSC_SUCCESS 1
#define AUDITSC_FAILURE 2
#define AUDITSC_RESULT(x) ( ((long)(x))<0?AUDITSC_FAILURE:AUDITSC_SUCCESS )
#ifdef CONFIG_AUDITSYSCALL
/* These are defined in auditsc.c */
/* Public API */
extern int audit_alloc(struct task_struct *task);
extern void audit_free(struct task_struct *task);
extern void audit_syscall_entry(struct task_struct *task,
extern void audit_syscall_entry(struct task_struct *task, int arch,
int major, unsigned long a0, unsigned long a1,
unsigned long a2, unsigned long a3);
extern void audit_syscall_exit(struct task_struct *task, int return_code);
extern void audit_syscall_exit(struct task_struct *task, int failed, long return_code);
extern void audit_getname(const char *name);
extern void audit_putname(const char *name);
extern void audit_inode(const char *name, const struct inode *inode);
@ -153,8 +193,8 @@ extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mo
#else
#define audit_alloc(t) ({ 0; })
#define audit_free(t) do { ; } while (0)
#define audit_syscall_entry(t,a,b,c,d,e) do { ; } while (0)
#define audit_syscall_exit(t,r) do { ; } while (0)
#define audit_syscall_entry(t,ta,a,b,c,d,e) do { ; } while (0)
#define audit_syscall_exit(t,f,r) do { ; } while (0)
#define audit_getname(n) do { ; } while (0)
#define audit_putname(n) do { ; } while (0)
#define audit_inode(n,i) do { ; } while (0)

22
kernel/auditsc.c
View File

@ -123,7 +123,7 @@ struct audit_context {
int major; /* syscall number */
unsigned long argv[4]; /* syscall arguments */
int return_valid; /* return code is valid */
int return_code;/* syscall return code */
long return_code;/* syscall return code */
int auditable; /* 1 if record should be written */
int name_count;
struct audit_names names[AUDIT_NAMES];
@ -135,6 +135,7 @@ struct audit_context {
uid_t uid, euid, suid, fsuid;
gid_t gid, egid, sgid, fsgid;
unsigned long personality;
int arch;
#if AUDIT_DEBUG
int put_count;
@ -348,6 +349,10 @@ static int audit_filter_rules(struct task_struct *tsk,
case AUDIT_PERS:
result = (tsk->personality == value);
break;
case AUDIT_ARCH:
if (ctx)
result = (ctx->arch == value);
break;
case AUDIT_EXIT:
if (ctx && ctx->return_valid)
@ -355,7 +360,7 @@ static int audit_filter_rules(struct task_struct *tsk,
break;
case AUDIT_SUCCESS:
if (ctx && ctx->return_valid)
result = (ctx->return_code >= 0);
result = (ctx->return_valid == AUDITSC_SUCCESS);
break;
case AUDIT_DEVMAJOR:
if (ctx) {
@ -648,8 +653,11 @@ static void audit_log_exit(struct audit_context *context)
audit_log_format(ab, "syscall=%d", context->major);
if (context->personality != PER_LINUX)
audit_log_format(ab, " per=%lx", context->personality);
audit_log_format(ab, " arch=%x", context->arch);
if (context->return_valid)
audit_log_format(ab, " exit=%d", context->return_code);
audit_log_format(ab, " success=%s exit=%ld",
(context->return_valid==AUDITSC_SUCCESS)?"yes":"no",
context->return_code);
audit_log_format(ab,
" a0=%lx a1=%lx a2=%lx a3=%lx items=%d"
" pid=%d loginuid=%d uid=%d gid=%d"
@ -773,7 +781,7 @@ static inline unsigned int audit_serial(void)
* then the record will be written at syscall exit time (otherwise, it
* will only be written if another part of the kernel requests that it
* be written). */
void audit_syscall_entry(struct task_struct *tsk, int major,
void audit_syscall_entry(struct task_struct *tsk, int arch, int major,
unsigned long a1, unsigned long a2,
unsigned long a3, unsigned long a4)
{
@ -827,6 +835,7 @@ void audit_syscall_entry(struct task_struct *tsk, int major,
if (!audit_enabled)
return;
context->arch = arch;
context->major = major;
context->argv[0] = a1;
context->argv[1] = a2;
@ -850,13 +859,13 @@ void audit_syscall_entry(struct task_struct *tsk, int major,
* filtering, or because some other part of the kernel write an audit
* message), then write out the syscall information. In call cases,
* free the names stored from getname(). */
void audit_syscall_exit(struct task_struct *tsk, int return_code)
void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code)
{
struct audit_context *context;
get_task_struct(tsk);
task_lock(tsk);
context = audit_get_context(tsk, 1, return_code);
context = audit_get_context(tsk, valid, return_code);
task_unlock(tsk);
/* Not having a context here is ok, since the parent may have
@ -869,6 +878,7 @@ void audit_syscall_exit(struct task_struct *tsk, int return_code)
context->in_syscall = 0;
context->auditable = 0;
if (context->previous) {
struct audit_context *new_context = context->previous;
context->previous = NULL;