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Subject[patch] 2.3.18ac10 binfmt_a.out fixes
I think I found some bug in the a.out code.

It seems to me that we are still checking if the binary-file-offset is
minor of the fs blocksize. So I disabled such checks as we don't
mmap(MAP_PRIVATE) the file anymore if the fd_offset is not page aligned.

Then there was one do_brk mapping at address zero intead of the address
where was want to load the binary.

As last thing I think the `start_addr & PAGE_MASK' was not necessary as
first because the old code was using the plain start_addr for doing the
mmap(MAP_PRIVATE). the start_addr is just forced to be page aligned in
i386. Anyway the current code make not too much sense anyway as it should
at least do something like:

start = start_addr & PAGE_MASK;
end = start_addr + size;
do_brk(start, end-start);

while right now it does:

do_brk(start_addr & PAGE_MASK, size);

I can't try the patch as I never had zmagic binaries under my hands.

--- 2.3.18ac10/fs/binfmt_aout.c Thu Sep 30 17:00:26 1999
+++ 2.3.18ac10-zmagic/fs/binfmt_aout.c Sat Oct 2 23:13:13 1999
@@ -270,7 +270,6 @@
unsigned long fd_offset;
unsigned long rlim;
int retval;
- static unsigned long error_time=0;

ex = *((struct exec *) bprm->buf); /* exec-header */
if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
@@ -282,6 +281,7 @@

fd_offset = N_TXTOFF(ex);

+#if 0
#ifdef __i386__
if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE) {
if((jiffies-error_time) >5)
@@ -296,6 +296,7 @@
bprm->dentry->d_inode->i_op &&
bprm->dentry->d_inode->i_op->get_block &&
(fd_offset < bprm->dentry->d_inode->i_sb->s_blocksize)) {
+ static unsigned long error_time=0;
if((jiffies-error_time) >5)
{
printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert binary.\n");
@@ -304,6 +305,7 @@
return -ENOEXEC;
}
#endif
+#endif

/* Check initial limits. This avoids letting people circumvent
* size limits imposed on them by creating programs with large
@@ -383,7 +385,7 @@
if (!file->f_op || !file->f_op->mmap || ((fd_offset & ~PAGE_MASK) != 0)) {
fput(file);
sys_close(fd);
- do_brk(0, ex.a_text+ex.a_data);
+ do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
read_exec(bprm->dentry, fd_offset,
(char *) N_TXTADDR(ex), ex.a_text+ex.a_data, 0);
flush_icache_range((unsigned long) N_TXTADDR(ex),
@@ -493,11 +495,13 @@
goto out_putf;
}

+#if 0
if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
(N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
goto out_putf;
}
+#endif

if (N_FLAGS(ex))
goto out_putf;
@@ -513,9 +517,7 @@
file->f_dentry->d_name.name
);

- do_mmap(NULL, start_addr & PAGE_MASK, ex.a_text + ex.a_data + ex.a_bss,
- PROT_READ | PROT_WRITE | PROT_EXEC,
- MAP_FIXED| MAP_PRIVATE, 0);
+ do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);

read_exec(file->f_dentry, N_TXTOFF(ex),
(char *)start_addr, ex.a_text + ex.a_data, 0);

I fixed the zero mapped address also in 2.2.13pre14 (I have not tried this
one too).

--- 2.2.13pre14/fs/binfmt_aout.c Tue Sep 28 18:32:37 1999
+++ /tmp/binfmt_aout.c Sat Oct 2 23:32:33 1999
@@ -424,7 +424,7 @@

if (!file->f_op || !file->f_op->mmap) {
sys_close(fd);
- do_mmap(NULL, 0, ex.a_text+ex.a_data,
+ do_mmap(NULL, N_TXTADDR(ex), ex.a_text+ex.a_data,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE, 0);
read_exec(bprm->dentry, fd_offset,
Andrea


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