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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-05-07 22:55:41 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-05-08 12:15:11 -0400 |
| commit | 4dd537aca25dd2e0e8aca8b8923930cbe6240003 (patch) | |
| tree | 4237d1d2cd0c827fd2d3edd8040b5fd6a9337375 | |
| parent | 9e298e8604088a600d8100a111a532a9d342af09 (diff) | |
| download | linux-4dd537aca25dd2e0e8aca8b8923930cbe6240003.tar.gz | |
tracing: uprobes: Re-enable $comm support for uprobe events
Since commit 533059281ee5 ("tracing: probeevent: Introduce new
argument fetching code") dropped the $comm support from uprobe
events, this re-enables it.
For $comm support, uses strlcpy() instead of strncpy_from_user()
to copy current task's comm. Because it is in the kernel space,
strncpy_from_user() always fails to copy the comm.
This also uses strlen() instead of strnlen_user() to measure the
length of the comm.
Note that this uses -ECOMM as a token value to fetch the comm
string. If the user-space pointer points -ECOMM, it will be
translated to task->comm.
Link: http://lkml.kernel.org/r/155723734162.9149.4042756162201097965.stgit@devnote2
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Reported-by: Andreas Ziegler <andreas.ziegler@fau.de>
Acked-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/trace_probe.h | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_uprobe.c | 13 |
2 files changed, 12 insertions, 2 deletions
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index b7737666c1a8..f9a8c632188b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -124,6 +124,7 @@ struct fetch_insn { /* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */ #define FETCH_INSN_MAX 16 +#define FETCH_TOKEN_COMM (-ECOMM) /* Fetch type information table */ struct fetch_type { diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index cd8750a72768..eb7e06b54741 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -156,7 +156,10 @@ fetch_store_string(unsigned long addr, void *dest, void *base) if (unlikely(!maxlen)) return -ENOMEM; - ret = strncpy_from_user(dst, src, maxlen); + if (addr == FETCH_TOKEN_COMM) + ret = strlcpy(dst, current->comm, maxlen); + else + ret = strncpy_from_user(dst, src, maxlen); if (ret >= 0) { if (ret == maxlen) dst[ret - 1] = '\0'; @@ -180,7 +183,10 @@ fetch_store_strlen(unsigned long addr) int len; void __user *vaddr = (void __force __user *) addr; - len = strnlen_user(vaddr, MAX_STRING_SIZE); + if (addr == FETCH_TOKEN_COMM) + len = strlen(current->comm) + 1; + else + len = strnlen_user(vaddr, MAX_STRING_SIZE); return (len > MAX_STRING_SIZE) ? 0 : len; } @@ -220,6 +226,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, case FETCH_OP_IMM: val = code->immediate; break; + case FETCH_OP_COMM: + val = FETCH_TOKEN_COMM; + break; case FETCH_OP_FOFFS: val = translate_user_vaddr(code->immediate); break; |