Changes between Version 11 and Version 12 of Dev/KernelHack/COINS/worklog/201111

Timestamp:

Nov 25, 2011 2:15:56 AM (13 years ago)

Author:

mitty

Comment:

--

Dev/KernelHack/COINS/worklog/201111

@@ -2444 +2444 @@
 Continuing.
 }}}
+
+ = 11/23 =
+ == instead of char*, use typedef struct DATA ==
+ * s0711489@ubuntu-lucid64:~$ sudo insmod stackmod.ko
+{{{
+Nov 23 01:54:02 ubuntu-lucid64 kernel: [  242.821597] stackmod is loaded
+Nov 23 01:54:02 ubuntu-lucid64 kernel: [  242.821601] stackmod: 128 entry, major is 251, minor is 0
+Nov 23 01:54:02 ubuntu-lucid64 kernel: [  242.821616] stackmod: create /proc/stackmod
+Nov 23 01:54:02 ubuntu-lucid64 kernel: [  242.821618] stackmod is added successfully
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ sudo mknod /dev/stack c 251 0
+ * s0711489@ubuntu-lucid64:~$ sudo chmod 666 /dev/stack
+
+ * s0711489@ubuntu-lucid64:~$ echo hoge > /dev/stack
+{{{
+Nov 23 01:55:26 ubuntu-lucid64 kernel: [  327.080724] stackmod is opened
+Nov 23 01:55:26 ubuntu-lucid64 kernel: [  327.080773] stackmod is written
+Nov 23 01:55:26 ubuntu-lucid64 kernel: [  327.080784] stackmod is released
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 1
+}}}
+{{{
+Nov 23 01:55:44 ubuntu-lucid64 kernel: [  344.897310] /proc/stackmod is read
+Nov 23 01:55:44 ubuntu-lucid64 kernel: [  344.897328] /proc/stackmod is read
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+cat: /dev/stack: Bad address
+}}}
+{{{
+Nov 23 01:56:09 ubuntu-lucid64 kernel: [  370.036240] stackmod is opened
+Nov 23 01:56:09 ubuntu-lucid64 kernel: [  370.036253] stackmod is read
+Nov 23 01:56:09 ubuntu-lucid64 kernel: [  370.036346] stackmod: copy_to_user failed
+Nov 23 01:56:09 ubuntu-lucid64 kernel: [  370.036471] stackmod is released
+}}}
+  * buggy
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 1
+}}}
+
+ === check what is bug with gdb ===
+ * s0711489@ubuntu-lucid64:~$ sudo insmod stackmod.ko entry=4
+ * s0711489@ubuntu-lucid64:~$ sudo mknod /dev/stack c 251 0
+ * s0711489@ubuntu-lucid64:~$ sudo chmod 666 /dev/stack
+
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.text
+{{{
+0xffffffffa0056000
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.data
+{{{
+0xffffffffa00566b8
+}}}
+ * s0711489@ubuntu-lucid64:~$ cat /sys/module/stackmod/sections/.bss
+{{{
+0xffffffffa00568f0
+}}}
+
+ * gdb
+{{{
+(gdb) file vmlinux
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/vmlinux...(no debugging symbols found)...done.
+(gdb) add-symbol-file ../../04/stackmod/stackmod.o 0xffffffffa0056000 -s .data 0xffffffffa00566b8 -s .bss 0xffffffffa00568f0
+add symbol table from file "../../04/stackmod/stackmod.o" at
+        .text_addr = 0xffffffffa0056000
+        .data_addr = 0xffffffffa00566b8
+        .bss_addr = 0xffffffffa00568f0
+(y or n) y
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.o...done.
+(gdb) target remote localhost:8864
+Remote debugging using localhost:8864
+0xffffffff810097a9 in native_safe_halt ()
+    at /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/x86_64/arch/x86/include/asm/irqflags.h:49
+49              asm volatile("sti; hlt": : :"memory");
+(gdb) b stackmod_read
+Breakpoint 1 at 0xffffffffa00560b4: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 62.
+(gdb) b stackmod_write
+Breakpoint 2 at 0xffffffffa00561e0: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 105.
+(gdb) b stackmod_proc_read
+Breakpoint 3 at 0xffffffffa00561a3: file /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c, line 153.
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 0
+}}}
+{{{
+Breakpoint 3, stackmod_proc_read (page=0xffff88001d9a9000 "p\227\232\035",
+    start=0xffff88001b95fe90, off=0, count=3072, eof=0xffff88001b95fe9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:153
+153     ) {
+(gdb) p stack
+$1 = {data = 0xffff88001b7c7940, depth = 0, errno = 0}
+(gdb) p stack.data
+$2 = (DATA *) 0xffff88001b7c7940
+(gdb) ptype stack.data
+type = struct kernel_module_stack_data {
+    int length;
+    char *content;
+} *
+(gdb) ptype stack.data[0]
+type = struct kernel_module_stack_data {
+    int length;
+    char *content;
+}
+(gdb) p stack.data[0]
+$3 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) p stack.data[1]
+$4 = {length = 0, content = 0x0}
+(gdb) p stack.data[2]
+$5 = {length = 0,
+  content = 0x2e2e02020010e071 <Address 0x2e2e02020010e071 out of bounds>}
+(gdb) c
+Continuing.
+
+Breakpoint 3, stackmod_proc_read (page=0xffff88001d9a9000 "stack: 0\n",
+    start=0xffff88001b95fe90, off=9, count=3072, eof=0xffff88001b95fe9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:153
+153     ) {
+(gdb) finish
+Run till exit from #0  stackmod_proc_read (
+    page=0xffff88001d9a9000 "stack: 0\n", start=0xffff88001b95fe90, off=9,
+    count=3072, eof=0xffff88001b95fe9c, data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:153
+__proc_file_read (file=<value optimized out>, buf=0x1420000 "stack: 0\n",
+    nbytes=32768, ppos=0xffff88001b95ff48) at fs/proc/generic.c:125
+125                     if (n == 0)   /* end of file */
+Could not fetch register "orig_rax"; remote failure reply 'E00'
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /dev/stack
+{{{
+Nov 23 02:43:46 ubuntu-lucid64 kernel: [ 2449.923317] stackmod is opened
+Nov 23 02:43:46 ubuntu-lucid64 kernel: [ 2514.778526] stackmod is read
+Nov 23 02:43:46 ubuntu-lucid64 kernel: [ 2538.311203] stackmod is released
+}}}
+{{{
+Breakpoint 1, stackmod_read (filep=0xffff88001b90a240,
+    buf_user=0x189a000 <Address 0x189a000 out of bounds>, size=32768,
+    offset=0xffff88001bb19f48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:62
+62      ) {
+(gdb) p p
+$6 = <value optimized out>
+(gdb) p stack.depth
+$7 = 0
+
+(snip)
+
+(gdb) n
+66              printk(KERN_DEBUG MODNAME " is read\n");
+(gdb)
+62      ) {
+(gdb)
+66              printk(KERN_DEBUG MODNAME " is read\n");
+(gdb)
+68              if (size == 0) {
+(gdb)
+71              if (stack.depth == 0) {
+(gdb)
+101     }
+(gdb)
+vfs_read (file=0xffff88001b90a240,
+    buf=0x189a000 <Address 0x189a000 out of bounds>,
+    count=<value optimized out>, pos=0xffff88001bb19f48) at fs/read_write.c:313
+313                     if (ret > 0) {
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ echo depth=0 > /dev/stack
+{{{
+Nov 23 02:47:16 ubuntu-lucid64 kernel: [ 2651.841249] stackmod is opened
+Nov 23 02:47:41 ubuntu-lucid64 kernel: [ 2724.502176] stackmod is written
+Nov 23 02:50:07 ubuntu-lucid64 kernel: [ 2916.725803] stackmod is released
+}}}
+{{{
+Breakpoint 2, stackmod_write (filep=0xffff88001b984240,
+    buf_user=0x126ac08 "depth=0\n /usr/bin/xzdec\nusr/sbin/update-alternatives\n\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337", <incomplete sequence \337>..., size=8,
+    offset=0xffff88001b8dff48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:105
+105     ) {
+(gdb) p p
+$8 = <value optimized out>
+(gdb) p stack
+$9 = {data = 0xffff88001b7c7940, depth = 0, errno = 0}
+(gdb) p stack.data[0]
+$10 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) n
+108             printk(KERN_DEBUG MODNAME " is written\n");
+(gdb)
+105     ) {
+(gdb)
+108             printk(KERN_DEBUG MODNAME " is written\n");
+(gdb)
+110             if (size == 0) {
+(gdb)
+113             if (stack.depth >= entry) {
+(gdb)
+117             if (buf_user == NULL) {
+(gdb)
+122             p.content = (char *) kmalloc(size * sizeof(char), GFP_KERNEL);
+(gdb)
+123             if (p.content == NULL) {
+(gdb)
+122             p.content = (char *) kmalloc(size * sizeof(char), GFP_KERNEL);
+(gdb)
+123             if (p.content == NULL) {
+(gdb)
+129             if (copy_from_user(p.content, buf_user, size) != 0) {
+(gdb) p stack.data[0]
+$11 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) n
+136             stack.depth++;
+(gdb) p stack.data[0]
+$12 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) p stack.data[0].content
+$13 = 0xffff88001b7c7988 "\210y|\033"
+(gdb) p size
+$14 = 0
+(gdb) p buf_user
+$15 = 0x126ac08 "depth=0\n /usr/bin/xzdec\nusr/sbin/update-alternatives\n\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337", <incomplete sequence \337>...
+(gdb) n
+140             return size;
+(gdb) p stack
+$16 = {data = 0xffff88001b7c7940, depth = 1, errno = 0}
+(gdb) p stack.data[0]
+$17 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ echo depth=1 > /dev/stack
+{{{
+Nov 23 02:51:53 ubuntu-lucid64 kernel: [ 2955.599055] stackmod is opened
+Nov 23 02:51:53 ubuntu-lucid64 kernel: [ 2986.156722] stackmod is written
+Nov 23 02:53:51 ubuntu-lucid64 kernel: [ 3139.258180] stackmod is released
+}}}
+{{{
+Breakpoint 2, stackmod_write (filep=0xffff88001b80e9c0,
+    buf_user=0x126ac08 "depth=1\n /usr/bin/xzdec\nusr/sbin/update-alternatives\n\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337", <incomplete sequence \337>..., size=8,
+    offset=0xffff88001b8dff48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:105
+105     ) {
+(gdb) p size
+$18 = 8
+(gdb) n
+108             printk(KERN_DEBUG MODNAME " is written\n");
+(gdb)
+105     ) {
+(gdb)
+108             printk(KERN_DEBUG MODNAME " is written\n");
+(gdb)
+110             if (size == 0) {
+(gdb)
+113             if (stack.depth >= entry) {
+(gdb)
+117             if (buf_user == NULL) {
+(gdb)
+122             p.content = (char *) kmalloc(size * sizeof(char), GFP_KERNEL);
+(gdb) l
+117             if (buf_user == NULL) {
+118                     return -EINVAL;
+119             }
+120
+121             p = stack.data[stack.depth];
+122             p.content = (char *) kmalloc(size * sizeof(char), GFP_KERNEL);
+123             if (p.content == NULL) {
+124                     printk(KERN_WARNING MODNAME ": (char *) kmalloc failed\n");
+125                     return -ENOMEM;
+126             }
+(gdb) n
+123             if (p.content == NULL) {
+(gdb) p p.content
+$19 = 0x0
+(gdb) n
+122             p.content = (char *) kmalloc(size * sizeof(char), GFP_KERNEL);
+(gdb)
+123             if (p.content == NULL) {
+(gdb) p p.content
+$20 = 0x0
+(gdb) n
+129             if (copy_from_user(p.content, buf_user, size) != 0) {
+(gdb)
+136             stack.depth++;
+(gdb) p p.content
+$21 = 0x0
+(gdb) p size
+$22 = 0
+(gdb) p p
+$23 = <value optimized out>
+(gdb) p stack.data
+$24 = (DATA *) 0xffff88001b7c7940
+(gdb) p stack
+$25 = {data = 0xffff88001b7c7940, depth = 1, errno = 0}
+(gdb) p stack[1]
+Structure has no component named operator[].
+(gdb) p stack.data[1]
+$26 = {length = 0, content = 0x0}
+(gdb) n
+140             return size;
+(gdb) p size
+$27 = 0
+(gdb) finish
+Run till exit from #0  stackmod_write (filep=<value optimized out>,
+    buf_user=0x126ac08 "depth=1\n /usr/bin/xzdec\nusr/sbin/update-alternatives\n\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337", <incomplete sequence \337>..., size=0,
+    offset=0xffff88001b8dff48)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:140
+0xffffffff810df5a3 in vfs_write (file=0xffff88001b80e9c0,
+    buf=0x126ac08 "depth=1\n /usr/bin/xzdec\nusr/sbin/update-alternatives\n\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337\337", <incomplete sequence \337>...,
+    count=<value optimized out>, pos=0xffff88001b8dff48) at fs/read_write.c:366
+366                             ret = file->f_op->write(file, buf, count, pos);
+Could not fetch register "orig_rax"; remote failure reply 'E00'
+(gdb) c
+Continuing.
+}}}
+
+ * s0711489@ubuntu-lucid64:~$ cat /proc/stackmod
+{{{
+stack: 2
+}}}
+{{{
+Breakpoint 3, stackmod_proc_read (page=0xffff88001d9a9000 "stack: 0\n",
+    start=0xffff88001b8ade90, off=0, count=3072, eof=0xffff88001b8ade9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:153
+153     ) {
+(gdb) p stack
+$28 = {data = 0xffff88001b7c7940, depth = 2, errno = 0}
+(gdb) p stack.data[0]
+$29 = {length = 461142784, content = 0xffff88001b7c7988 "\210y|\033"}
+(gdb) p stack.data[1]
+$30 = {length = 0, content = 0x0}
+(gdb) p stack.data[2]
+$31 = {length = 0,
+  content = 0x2e2e02020010e071 <Address 0x2e2e02020010e071 out of bounds>}
+(gdb) ptype stack
+type = struct kernel_module_stack {
+    DATA *data;
+    int depth;
+    int errno;
+}
+(gdb) ptype stack.data
+type = struct kernel_module_stack_data {
+    int length;
+    char *content;
+} *
+(gdb) ptype stack.data[0]
+type = struct kernel_module_stack_data {
+    int length;
+    char *content;
+}
+(gdb) ptype stack.data[0].content
+type = char *
+(gdb) c
+Continuing.
+
+Breakpoint 3, stackmod_proc_read (page=0xffff88001d9a9000 "stack: 2\n",
+    start=0xffff88001b8ade90, off=9, count=3072, eof=0xffff88001b8ade9c,
+    data=0x0)
+    at /home/ugrad/07/s0711489/coursework/KernelHack/04/stackmod/stackmod.c:153
+153     ) {
+(gdb) c
+Continuing.
+}}}