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wordexp: Rewrite parse_tilde to use struct scratch_buffer [BZ #18023]

This commit is contained in:
Florian Weimer 2018-06-27 17:54:44 +02:00
parent 95f8ae8c83
commit 4272059de2
2 changed files with 34 additions and 16 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2018-06-27 Florian Weimer <fweimer@redhat.com>
[BZ #18023]
* posix/wordexp.c (parse_tilde): Use struct scratch_buffer
instead of extend_alloca.
2018-06-26 Joseph Myers <joseph@codesourcery.com> 2018-06-26 Joseph Myers <joseph@codesourcery.com>
[BZ #13888] [BZ #13888]

44
posix/wordexp.c
View File

@ -17,7 +17,6 @@
License along with the GNU C Library; if not, see License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */ <http://www.gnu.org/licenses/>. */
#include <alloca.h>
#include <ctype.h> #include <ctype.h>
#include <errno.h> #include <errno.h>
#include <fcntl.h> #include <fcntl.h>
@ -41,6 +40,7 @@
#include <wchar.h> #include <wchar.h>
#include <wordexp.h> #include <wordexp.h>
#include <kernel-features.h> #include <kernel-features.h>
#include <scratch_buffer.h>
#include <libc-lock.h> #include <libc-lock.h>
#include <_itoa.h> #include <_itoa.h>
@ -299,12 +299,7 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
if (i == 1 + *offset) if (i == 1 + *offset)
{ {
/* Tilde appears on its own */ /* Tilde appears on its own */
uid_t uid;
struct passwd pwd, *tpwd;
int buflen = 1000;
char* home; char* home;
char* buffer;
int result;
/* POSIX.2 says ~ expands to $HOME and if HOME is unset the /* POSIX.2 says ~ expands to $HOME and if HOME is unset the
results are unspecified. We do a lookup on the uid if results are unspecified. We do a lookup on the uid if
@ -319,25 +314,38 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
} }
else else
{ {
uid = __getuid (); struct passwd pwd, *tpwd;
buffer = __alloca (buflen); uid_t uid = __getuid ();
int result;
struct scratch_buffer tmpbuf;
scratch_buffer_init (&tmpbuf);
while ((result = __getpwuid_r (uid, &pwd, buffer, buflen, &tpwd)) != 0 while ((result = __getpwuid_r (uid, &pwd,
tmpbuf.data, tmpbuf.length,
&tpwd)) != 0
&& errno == ERANGE) && errno == ERANGE)
buffer = extend_alloca (buffer, buflen, buflen + 1000); if (!scratch_buffer_grow (&tmpbuf))
return WRDE_NOSPACE;
if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL) if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL)
{ {
*word = w_addstr (*word, word_length, max_length, pwd.pw_dir); *word = w_addstr (*word, word_length, max_length, pwd.pw_dir);
if (*word == NULL) if (*word == NULL)
return WRDE_NOSPACE; {
scratch_buffer_free (&tmpbuf);
return WRDE_NOSPACE;
}
} }
else else
{ {
*word = w_addchar (*word, word_length, max_length, '~'); *word = w_addchar (*word, word_length, max_length, '~');
if (*word == NULL) if (*word == NULL)
return WRDE_NOSPACE; {
scratch_buffer_free (&tmpbuf);
return WRDE_NOSPACE;
}
} }
scratch_buffer_free (&tmpbuf);
} }
} }
else else
@ -345,13 +353,15 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
/* Look up user name in database to get home directory */ /* Look up user name in database to get home directory */
char *user = strndupa (&words[1 + *offset], i - (1 + *offset)); char *user = strndupa (&words[1 + *offset], i - (1 + *offset));
struct passwd pwd, *tpwd; struct passwd pwd, *tpwd;
int buflen = 1000;
char* buffer = __alloca (buflen);
int result; int result;
struct scratch_buffer tmpbuf;
scratch_buffer_init (&tmpbuf);
while ((result = __getpwnam_r (user, &pwd, buffer, buflen, &tpwd)) != 0 while ((result = __getpwnam_r (user, &pwd, tmpbuf.data, tmpbuf.length,
&tpwd)) != 0
&& errno == ERANGE) && errno == ERANGE)
buffer = extend_alloca (buffer, buflen, buflen + 1000); if (!scratch_buffer_grow (&tmpbuf))
return WRDE_NOSPACE;
if (result == 0 && tpwd != NULL && pwd.pw_dir) if (result == 0 && tpwd != NULL && pwd.pw_dir)
*word = w_addstr (*word, word_length, max_length, pwd.pw_dir); *word = w_addstr (*word, word_length, max_length, pwd.pw_dir);
@ -363,6 +373,8 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length,
*word = w_addstr (*word, word_length, max_length, user); *word = w_addstr (*word, word_length, max_length, user);
} }
scratch_buffer_free (&tmpbuf);
*offset = i - 1; *offset = i - 1;
} }
return *word ? 0 : WRDE_NOSPACE; return *word ? 0 : WRDE_NOSPACE;