In Documentation/trace/kprobetrace.txt, it says
@SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
However, the parser doesn't parse minus offset correctly, since commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned") drops minus ("-") offset support for kprobe probe address usage.
This fixes the traceprobe_split_symbol_offset() to parse minus offset again with checking the offset range, and add a minus offset check in kprobe probe address usage.
Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned") Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- Changes in v2.1: - Fix to ensure the offset value is less than LONG_MAX. - Fail if the offset is minus when traceprobe_split_symbol_offset() is used for the probe address. - Add Fixes tag. --- kernel/trace/trace_kprobe.c | 4 ++-- kernel/trace/trace_probe.c | 15 ++++++++++----- kernel/trace/trace_probe.h | 2 +- 3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 5ce9b8cf7be3..b5b1d8aa47d6 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -667,7 +667,7 @@ static int create_trace_kprobe(int argc, char **argv) char *symbol = NULL, *event = NULL, *group = NULL; int maxactive = 0; char *arg; - unsigned long offset = 0; + long offset = 0; void *addr = NULL; char buf[MAX_EVENT_NAME_LEN];
@@ -755,7 +755,7 @@ static int create_trace_kprobe(int argc, char **argv) symbol = argv[1]; /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); - if (ret) { + if (ret || offset < 0) { pr_info("Failed to parse either an address or a symbol.\n"); return ret; } diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index d59357308677..ec3856147fdd 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -320,21 +320,26 @@ static fetch_func_t get_fetch_size_function(const struct fetch_type *type, }
/* Split symbol and offset. */ -int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset) +int traceprobe_split_symbol_offset(char *symbol, long *offset) { + unsigned long ul; char *tmp; int ret;
if (!offset) return -EINVAL;
- tmp = strchr(symbol, '+'); + tmp = strpbrk(symbol, "+-"); if (tmp) { - /* skip sign because kstrtoul doesn't accept '+' */ - ret = kstrtoul(tmp + 1, 0, offset); + ret = kstrtoul(tmp + 1, 0, &ul); if (ret) return ret; - + if (ul > LONG_MAX) + return -E2BIG; + if (*tmp == '-') + *offset = -ul; + else + *offset = ul; *tmp = '\0'; } else *offset = 0; diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 0745f895f780..75daff22ccea 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char *name, extern void traceprobe_update_arg(struct probe_arg *arg); extern void traceprobe_free_probe_arg(struct probe_arg *arg);
-extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset); +extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
/* Sum up total data length for dynamic arraies (strings) */ static nokprobe_inline int
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