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Fixed a bug in kstrncpy() that caused mayhem whenever the buffer to be

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copied into was the same size as the source string - it will keep on
filling with zeroes forever. This was a signed/unsigned bug, fixed by
making the kstrncpy argument ssize_t instead of size_t. This bug was
triggered by Chris Young <teddga@earthlink.net>, by dazzling coincedence -
changing OS_VERSION into something with one more character (exactly the
same size as the buffer in the kinfo struct).

Also noticed that the kstrncpy() call didn't null-terminate the strings
if necessary, also fixed.
This commit is contained in:
Ben Gras 2005-07-13 14:46:11 +00:00
parent 0f746219fc
commit f96645a4eb
3 changed files with 6 additions and 4 deletions
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2
kernel/klibc.c
View file

@ -214,7 +214,7 @@ PUBLIC int kstrncmp(register const char *s1, register const char *s2, register s
/*=========================================================================*
* kstrncpy *
*=========================================================================*/
PUBLIC char *kstrncpy(char *ret, register const char *s2, register size_t n)
PUBLIC char *kstrncpy(char *ret, register const char *s2, register ssize_t n)
{
register char *s1 = ret;
while((n-- > 0) && (*s1++ = *s2++)) /* copy up to n chars */

2
kernel/proto.h
View file

@ -24,7 +24,7 @@ _PROTOTYPE( size_t kstrlen, (const char *s));
_PROTOTYPE( int kstrncmp,
(register const char *s1, register const char *s2, register size_t n));
_PROTOTYPE( char *kstrncpy,
(char *s1, register const char *s2, register const size_t n));
(char *s1, register const char *s2, register const ssize_t n));
#define karg(arg) (karg_t) (arg)
_PROTOTYPE( void kprintf, (const char *fmt, karg_t arg) );

6
kernel/start.c
View file

@ -55,8 +55,10 @@ U16_t parmoff, parmsize; /* boot parameters offset and length */
/* Record miscellaneous information for user-space servers. */
kinfo.nr_procs = NR_PROCS;
kinfo.nr_tasks = NR_TASKS;
kstrncpy(kinfo.release, OS_RELEASE, 4);
kstrncpy(kinfo.version, OS_VERSION, 4);
kstrncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
kinfo.release[sizeof(kinfo.release)-1] = '\0';
kstrncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
kinfo.version[sizeof(kinfo.version)-1] = '\0';
kinfo.proc_addr = (vir_bytes) proc;
kinfo.kmem_base = vir2phys(0);
kinfo.kmem_size = (phys_bytes) &end;