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Cleaned up Erik's fgets -> read patch and fixed a buffer overflow

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This commit is contained in:
Robert Griebl 2002-06-04 19:33:58 +00:00
parent c06391be0d
commit bc28f7a1e1
1 changed files with 38 additions and 36 deletions
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74
modutils/modprobe.c
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@ -44,9 +44,38 @@ static struct dep_t *depend;
static int autoclean, show_only, quiet, do_syslog, verbose; static int autoclean, show_only, quiet, do_syslog, verbose;
/* Jump through hoops to simulate how fgets() grabs just one line at a
* time... Don't use any stdio since modprobe gets called from a kernel
* thread and stdio junk can overflow the limited stack...
*/
static char *reads ( int fd, char *buffer, size_t len )
{
int n = read ( fd, buffer, len );
if ( n > 0 ) {
char *p;
buffer [len-1] = 0;
p = strchr ( buffer, '\n' );
if ( p ) {
off_t offset;
offset = lseek ( fd, 0L, SEEK_CUR ); // Get the current file descriptor offset
lseek ( fd, offset-n + (p-buffer) + 1, SEEK_SET ); // Set the file descriptor offset to right after the \n
p[1] = 0;
}
return buffer;
}
else
return 0;
}
static struct dep_t *build_dep ( void ) static struct dep_t *build_dep ( void )
{ {
int fd, n; int fd;
struct utsname un; struct utsname un;
struct dep_t *first = 0; struct dep_t *first = 0;
struct dep_t *current = 0; struct dep_t *current = 0;
@ -66,27 +95,13 @@ static struct dep_t *build_dep ( void )
strcat ( filename, un.release ); strcat ( filename, un.release );
strcat ( filename, "/modules.dep" ); strcat ( filename, "/modules.dep" );
if ((fd = open ( filename, O_RDONLY )) < 0) if (( fd = open ( filename, O_RDONLY )) < 0 )
return 0; return 0;
while ( (n = read(fd, buffer, 255)) > 0) { while ( reads ( fd, buffer, sizeof( buffer ))) {
int l; int l = xstrlen ( buffer );
char *p = 0; char *p = 0;
/* Jump through hoops to simulate how fgets() grabs just one line at a
* time... Don't use any stdio since modprobe gets called from a kernel
* thread and stdio junk can overflow the limited stack... */
p = strchr ( buffer, '\n' );
if (p) {
off_t offset;
/* Get the current file descriptor offset */
offset = lseek(fd, 0L, SEEK_CUR);
/* Set the file descriptor offset to right after the \n */
lseek(fd, offset-n+p-buffer+1, SEEK_SET);
*(p+1)='\0';
}
l = xstrlen ( buffer );
while ( isspace ( buffer [l-1] )) { while ( isspace ( buffer [l-1] )) {
buffer [l-1] = 0; buffer [l-1] = 0;
l--; l--;
@ -182,29 +197,16 @@ static struct dep_t *build_dep ( void )
// alias parsing is not 100% correct (no correct handling of continuation lines within an alias) ! // alias parsing is not 100% correct (no correct handling of continuation lines within an alias) !
if ((fd = open ( "/etc/modules.conf", O_RDONLY )) < 0) if (( fd = open ( "/etc/modules.conf", O_RDONLY )) < 0 )
if ((fd = open ( "/etc/conf.modules", O_RDONLY )) < 0) if (( fd = open ( "/etc/conf.modules", O_RDONLY )) < 0 )
return first; return first;
continuation_line = 0; continuation_line = 0;
while ( read(fd, buffer, 255) > 0) { while ( reads ( fd, buffer, sizeof( buffer ))) {
int l; int l;
char *p; char *p;
/* Jump through hoops to simulate how fgets() grabs just one line at a p = strchr ( buffer, '#' );
* time... Don't use any stdio since modprobe gets called from a kernel
* thread and stdio junk can overflow the limited stack... */
p = strchr ( buffer, '\n' );
if (p) {
off_t offset;
/* Get the current file descriptor offset */
offset = lseek(fd, 0L, SEEK_CUR);
/* Set the file descriptor offset to right after the \n */
lseek(fd, offset-n+p-buffer+1, SEEK_SET);
*(p+1)='\0';
}
p = strchr ( buffer, '#' );
if ( p ) if ( p )
*p = 0; *p = 0;