5ac4837841
As the seq_buf->len will soon be +1 size when there's an overflow, we must use trace_seq_used() or seq_buf_used() methods to get the real length. This will prevent buffer overflow issues if just the len of the seq_buf descriptor is used to copy memory. Link: http://lkml.kernel.org/r/20141114121911.09ba3d38@gandalf.local.home Reported-by: Petr Mladek <pmladek@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
138 lines
3.7 KiB
C
138 lines
3.7 KiB
C
#ifndef _LINUX_TRACE_SEQ_H
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#define _LINUX_TRACE_SEQ_H
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#include <linux/seq_buf.h>
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#include <asm/page.h>
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/*
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* Trace sequences are used to allow a function to call several other functions
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* to create a string of data to use (up to a max of PAGE_SIZE).
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*/
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struct trace_seq {
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unsigned char buffer[PAGE_SIZE];
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struct seq_buf seq;
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int full;
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};
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static inline void
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trace_seq_init(struct trace_seq *s)
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{
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seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
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s->full = 0;
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}
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/**
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* trace_seq_used - amount of actual data written to buffer
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* @s: trace sequence descriptor
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*
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* Returns the amount of data written to the buffer.
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*
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* IMPORTANT!
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*
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* Use this instead of @s->seq.len if you need to pass the amount
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* of data from the buffer to another buffer (userspace, or what not).
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* The @s->seq.len on overflow is bigger than the buffer size and
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* using it can cause access to undefined memory.
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*/
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static inline int trace_seq_used(struct trace_seq *s)
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{
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return seq_buf_used(&s->seq);
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}
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/**
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* trace_seq_buffer_ptr - return pointer to next location in buffer
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* @s: trace sequence descriptor
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*
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* Returns the pointer to the buffer where the next write to
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* the buffer will happen. This is useful to save the location
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* that is about to be written to and then return the result
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* of that write.
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*/
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static inline unsigned char *
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trace_seq_buffer_ptr(struct trace_seq *s)
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{
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return s->buffer + seq_buf_used(&s->seq);
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}
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/**
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* trace_seq_has_overflowed - return true if the trace_seq took too much
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* @s: trace sequence descriptor
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*
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* Returns true if too much data was added to the trace_seq and it is
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* now full and will not take anymore.
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*/
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static inline bool trace_seq_has_overflowed(struct trace_seq *s)
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{
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return s->full || seq_buf_has_overflowed(&s->seq);
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}
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/*
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* Currently only defined when tracing is enabled.
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*/
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#ifdef CONFIG_TRACING
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extern __printf(2, 3)
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void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
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extern __printf(2, 0)
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void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
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extern void
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trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
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extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
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extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
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int cnt);
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extern void trace_seq_puts(struct trace_seq *s, const char *str);
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extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
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extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
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extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
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unsigned int len);
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extern int trace_seq_path(struct trace_seq *s, const struct path *path);
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extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
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int nmaskbits);
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#else /* CONFIG_TRACING */
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static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
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{
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}
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static inline void
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trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
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{
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}
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static inline void
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trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
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int nmaskbits)
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{
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}
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static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
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{
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return 0;
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}
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static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
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int cnt)
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{
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return 0;
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}
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static inline void trace_seq_puts(struct trace_seq *s, const char *str)
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{
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}
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static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
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{
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}
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static inline void
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trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
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{
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}
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static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
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unsigned int len)
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{
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}
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static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
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{
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return 0;
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}
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#endif /* CONFIG_TRACING */
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#endif /* _LINUX_TRACE_SEQ_H */
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