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| author | Tom Tromey <tromey@adacore.com> | 2021-05-17 12:55:18 -0600 |
|---|---|---|
| committer | Tom Tromey <tromey@adacore.com> | 2021-05-17 13:06:05 -0600 |
| commit | 591732169550b26608f186c9927f4cf9a47d99d5 (patch) | |
| tree | 62cb2535ab510fa1d484933b042fe871dde85130 | |
| parent | baea2f9d52d606f6b58a736420017c98351f5b5c (diff) | |
| download | gdb-591732169550b26608f186c9927f4cf9a47d99d5.zip gdb-591732169550b26608f186c9927f4cf9a47d99d5.tar.gz gdb-591732169550b26608f186c9927f4cf9a47d99d5.tar.bz2 | |
Fix ubsan build
I tried a build using the undefined behavior sanitizer, and gcc gave
this error:
In file included from /usr/include/string.h:495,
from ../gnulib/import/string.h:41,
from ../../binutils-gdb/gdb/../gdbsupport/common-defs.h:95,
from ../../binutils-gdb/gdb/nat/linux-osdata.c:20:
In function 'char* strncpy(char*, const char*, size_t)',
inlined from 'void time_from_time_t(char*, int, TIME_T)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:923:15,
inlined from 'void time_from_time_t(char*, int, TIME_T)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:911:1,
inlined from 'void linux_xfer_osdata_sem(buffer*)' at ../../binutils-gdb/gdb/nat/linux-osdata.c:1082:22:
/usr/include/bits/string_fortified.h:106:34: error: 'char* __builtin_strncpy(char*, const char*, long unsigned int)' specified bound 32 equals destination size [-Werror=stringop-truncation]
This patch fixes the problem by subtracting one from the length
parameter to strncpy.
I changed a couple of other similar functions -- gcc does not warn
about these, but I didn't see any substantial difference between the
different cases, and I think these are just latent warnings, to be
triggered in the future by a change to inlining heuristics.
gdb/ChangeLog
2021-05-17 Tom Tromey <tromey@adacore.com>
* nat/linux-osdata.c (user_from_uid, time_from_time_t)
(group_from_gid): Subtract one from strncpy length.
| -rw-r--r-- | gdb/ChangeLog | 5 | ||||
| -rw-r--r-- | gdb/nat/linux-osdata.c | 6 |
2 files changed, 8 insertions, 3 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a7ee02c..39cdb3a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,10 @@ 2021-05-17 Tom Tromey <tromey@adacore.com> + * nat/linux-osdata.c (user_from_uid, time_from_time_t) + (group_from_gid): Subtract one from strncpy length. + +2021-05-17 Tom Tromey <tromey@adacore.com> + * source.c (add_path): Check 'p' before using 'p[-1]'. 2021-05-17 Tom Tromey <tromey@adacore.com> diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c index 7034dd8..12f66d3 100644 --- a/gdb/nat/linux-osdata.c +++ b/gdb/nat/linux-osdata.c @@ -212,7 +212,7 @@ user_from_uid (char *user, int maxlen, uid_t uid) if (pwentry) { - strncpy (user, pwentry->pw_name, maxlen); + strncpy (user, pwentry->pw_name, maxlen - 1); /* Ensure that the user name is null-terminated. */ user[maxlen - 1] = '\0'; } @@ -920,7 +920,7 @@ time_from_time_t (char *time, int maxlen, TIME_T seconds) characters long. */ char buf[30]; const char *time_str = ctime_r (&t, buf); - strncpy (time, time_str, maxlen); + strncpy (time, time_str, maxlen - 1); time[maxlen - 1] = '\0'; } } @@ -935,7 +935,7 @@ group_from_gid (char *group, int maxlen, gid_t gid) if (grentry) { - strncpy (group, grentry->gr_name, maxlen); + strncpy (group, grentry->gr_name, maxlen - 1); /* Ensure that the group name is null-terminated. */ group[maxlen - 1] = '\0'; } |