Avoid stringop-truncation errors

I configured with -fsanitize=address and built gdb.  linux-tdep.c and
ada-tasks.c failed to build due to some stringop-truncation errors,
e.g.:

In function ‘char* strncpy(char*, const char*, size_t)’,
    inlined from ‘int linux_fill_prpsinfo(elf_internal_linux_prpsinfo*)’ at ../../binutils-gdb/gdb/linux-tdep.c:1742:11,
    inlined from ‘char* linux_make_corefile_notes(gdbarch*, bfd*, int*)’ at ../../binutils-gdb/gdb/linux-tdep.c:1878:27:
/usr/include/bits/string_fortified.h:106:34: error: ‘char* __builtin_strncpy(char*, const char*, long unsigned int)’ specified bound 81 equals destination size [-Werror=stringop-truncation]

This patch fixes the problem by using "sizeof - 1" in the call to
strndup, as recommended in the GCC manual.  This doesn't make a
difference here because the next line, in all cases, sets the final
element to '\0' anyway.

gdb/ChangeLog
2020-03-20  Tom Tromey  <tromey@adacore.com>

	* ada-tasks.c (read_atcb): Use smaller length in strncpy call.
	* linux-tdep.c (linux_fill_prpsinfo): Use smaller length in
	strncpy call.
This commit is contained in:
Tom Tromey 2020-03-20 07:30:13 -06:00
parent 1773be9ea2
commit f67210ff1c
3 changed files with 10 additions and 3 deletions

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@ -1,3 +1,9 @@
2020-03-20 Tom Tromey <tromey@adacore.com>
* ada-tasks.c (read_atcb): Use smaller length in strncpy call.
* linux-tdep.c (linux_fill_prpsinfo): Use smaller length in
strncpy call.
2020-03-20 Tom Tromey <tromey@adacore.com> 2020-03-20 Tom Tromey <tromey@adacore.com>
* symmisc.c (maintenance_print_one_line_table): Use ui_out. * symmisc.c (maintenance_print_one_line_table): Use ui_out.

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@ -679,7 +679,8 @@ read_atcb (CORE_ADDR task_id, struct ada_task_info *task_info)
task_name = p + 2; task_name = p + 2;
/* Copy the task name. */ /* Copy the task name. */
strncpy (task_info->name, task_name, sizeof (task_info->name)); strncpy (task_info->name, task_name,
sizeof (task_info->name) - 1);
task_info->name[sizeof (task_info->name) - 1] = 0; task_info->name[sizeof (task_info->name) - 1] = 0;
} }
else else

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@ -1729,7 +1729,7 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
/* Copying the program name. Only the basename matters. */ /* Copying the program name. Only the basename matters. */
basename = lbasename (fname.get ()); basename = lbasename (fname.get ());
strncpy (p->pr_fname, basename, sizeof (p->pr_fname)); strncpy (p->pr_fname, basename, sizeof (p->pr_fname) - 1);
p->pr_fname[sizeof (p->pr_fname) - 1] = '\0'; p->pr_fname[sizeof (p->pr_fname) - 1] = '\0';
infargs = get_inferior_args (); infargs = get_inferior_args ();
@ -1739,7 +1739,7 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
if (infargs != NULL) if (infargs != NULL)
psargs = psargs + " " + infargs; psargs = psargs + " " + infargs;
strncpy (p->pr_psargs, psargs.c_str (), sizeof (p->pr_psargs)); strncpy (p->pr_psargs, psargs.c_str (), sizeof (p->pr_psargs) - 1);
p->pr_psargs[sizeof (p->pr_psargs) - 1] = '\0'; p->pr_psargs[sizeof (p->pr_psargs) - 1] = '\0';
xsnprintf (filename, sizeof (filename), "/proc/%d/stat", (int) pid); xsnprintf (filename, sizeof (filename), "/proc/%d/stat", (int) pid);