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correct an alignment mis-conception for malloc(0) returned regions.

OK deraadt@
OPENBSD_3_1
tdeval 23 years ago
parent
commit
77a7c73d5c
1 changed files with 25 additions and 14 deletions
  1. +25
    -14
      src/lib/libc/stdlib/malloc.c

+ 25
- 14
src/lib/libc/stdlib/malloc.c View File

@ -8,7 +8,7 @@
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: malloc.c,v 1.44 2001/11/01 07:00:51 mickey Exp $";
static char rcsid[] = "$OpenBSD: malloc.c,v 1.45 2001/12/05 22:54:01 tdeval Exp $";
#endif /* LIBC_SCCS and not lint */
/*
@ -726,19 +726,28 @@ malloc_make_chunks(bits)
}
}
bp->size = (1UL<<bits);
bp->shift = bits;
bp->total = bp->free = malloc_pagesize >> bits;
bp->page = pp;
/* memory protect the page allocated in the malloc(0) case */
if (bits == 0) {
bp->size = 0;
bp->shift = 1;
i = malloc_minsize-1;
while (i >>= 1)
bp->shift++;
bp->total = bp->free = malloc_pagesize >> bp->shift;
bp->page = pp;
k = mprotect(pp, malloc_pagesize, PROT_NONE);
if (k < 0) {
ifree(pp);
ifree(bp);
return 0;
}
} else {
bp->size = (1UL<<bits);
bp->shift = bits;
bp->total = bp->free = malloc_pagesize >> bits;
bp->page = pp;
}
/* set all valid bits in the bitmap */
@ -831,7 +840,7 @@ malloc_bytes(size)
k += (lp-bp->bits)*MALLOC_BITS;
k <<= bp->shift;
if (malloc_junk && bp->shift != 0)
if (malloc_junk && bp->size != 0)
memset((char *)bp->page + k, SOME_JUNK, bp->size);
return (u_char *)bp->page + k;
@ -924,7 +933,7 @@ irealloc(ptr, size)
} else if (*mp >= MALLOC_MAGIC) { /* Chunk allocation */
/* Check the pointer for sane values */
if (((u_long)ptr & ((*mp)->size-1))) {
if ((u_long)ptr & ((1UL<<((*mp)->shift))-1)) {
wrtwarning("modified (chunk-) pointer.\n");
return 0;
}
@ -957,7 +966,7 @@ irealloc(ptr, size)
if (p) {
/* copy the lesser of the two sizes, and free the old one */
/* Don't move from/to 0 sized region !!! */
if (osize != 1 && size != 0) {
if (osize != 0 && size != 0) {
if (osize < size)
memcpy(p, ptr, osize);
else
@ -1121,7 +1130,7 @@ free_bytes(ptr, index, info)
/* Find the chunk number on the page */
i = ((u_long)ptr & malloc_pagemask) >> info->shift;
if (((u_long)ptr & (info->size-1))) {
if ((u_long)ptr & ((1UL<<(info->shift))-1)) {
wrtwarning("modified (chunk-) pointer.\n");
return;
}
@ -1131,19 +1140,21 @@ free_bytes(ptr, index, info)
return;
}
if (malloc_junk && info->shift != 0)
if (malloc_junk && info->size != 0)
memset(ptr, SOME_JUNK, info->size);
info->bits[i/MALLOC_BITS] |= 1UL<<(i%MALLOC_BITS);
info->free++;
mp = page_dir + info->shift;
if (info->size != 0)
mp = page_dir + info->shift;
else
mp = page_dir;
if (info->free == 1) {
/* Page became non-full */
mp = page_dir + info->shift;
/* Insert in address order */
while (*mp && (*mp)->next && (*mp)->next->page < info->page)
mp = &(*mp)->next;
@ -1169,7 +1180,7 @@ free_bytes(ptr, index, info)
page_dir[ptr2index(info->page)] = MALLOC_FIRST;
/* If the page was mprotected, unprotect it before releasing it */
if (info->shift == 0) {
if (info->size == 0) {
mprotect(info->page, malloc_pagesize, PROT_READ|PROT_WRITE);
/* Do we have to care if mprotect succeeds here ? */
}


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