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797311bce5
Fix to record 0-length data to data_loc in fetch_store_string*() if it fails
to get the string data.
Currently those expect that the data_loc is updated by store_trace_args() if
it returns the error code. However, that does not work correctly if the
argument is an array of strings. In that case, store_trace_args() only clears
the first entry of the array (which may have no error) and leaves other
entries. So it should be cleared by fetch_store_string*() itself.
Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated
only if it is used (ret > 0 and argument is a dynamic data.)
Link: https://lore.kernel.org/all/168908496683.123124.4761206188794205601.stgit@devnote2/
Fixes: 40b53b7718 ("tracing: probeevent: Add array type support")
Cc: stable@vger.kernel.org
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
120 lines
2.9 KiB
C
120 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __TRACE_PROBE_KERNEL_H_
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#define __TRACE_PROBE_KERNEL_H_
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/*
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* This depends on trace_probe.h, but can not include it due to
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* the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
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* Which means that any other user must include trace_probe.h before including
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* this file.
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*/
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/* Return the length of string -- including null terminal byte */
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static nokprobe_inline int
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fetch_store_strlen_user(unsigned long addr)
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{
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const void __user *uaddr = (__force const void __user *)addr;
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return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
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}
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/* Return the length of string -- including null terminal byte */
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static nokprobe_inline int
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fetch_store_strlen(unsigned long addr)
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{
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int ret, len = 0;
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u8 c;
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if (addr < TASK_SIZE)
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return fetch_store_strlen_user(addr);
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#endif
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do {
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ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
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len++;
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} while (c && ret == 0 && len < MAX_STRING_SIZE);
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return (ret < 0) ? ret : len;
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}
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static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)
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{
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if (ret < 0)
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ret = 0;
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*(u32 *)dest = make_data_loc(ret, __dest - base);
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}
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/*
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* Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
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* with max length and relative data location.
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*/
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static nokprobe_inline int
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fetch_store_string_user(unsigned long addr, void *dest, void *base)
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{
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const void __user *uaddr = (__force const void __user *)addr;
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int maxlen = get_loc_len(*(u32 *)dest);
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void *__dest;
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long ret;
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if (unlikely(!maxlen))
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return -ENOMEM;
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__dest = get_loc_data(dest, base);
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ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
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set_data_loc(ret, dest, __dest, base);
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return ret;
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}
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/*
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* Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
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* length and relative data location.
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*/
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static nokprobe_inline int
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fetch_store_string(unsigned long addr, void *dest, void *base)
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{
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int maxlen = get_loc_len(*(u32 *)dest);
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void *__dest;
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long ret;
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if ((unsigned long)addr < TASK_SIZE)
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return fetch_store_string_user(addr, dest, base);
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#endif
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if (unlikely(!maxlen))
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return -ENOMEM;
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__dest = get_loc_data(dest, base);
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/*
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* Try to get string again, since the string can be changed while
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* probing.
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*/
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ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
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set_data_loc(ret, dest, __dest, base);
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return ret;
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}
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static nokprobe_inline int
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probe_mem_read_user(void *dest, void *src, size_t size)
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{
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const void __user *uaddr = (__force const void __user *)src;
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return copy_from_user_nofault(dest, uaddr, size);
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}
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static nokprobe_inline int
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probe_mem_read(void *dest, void *src, size_t size)
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{
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#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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if ((unsigned long)src < TASK_SIZE)
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return probe_mem_read_user(dest, src, size);
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#endif
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return copy_from_kernel_nofault(dest, src, size);
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}
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#endif /* __TRACE_PROBE_KERNEL_H_ */
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