78%
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In the Linux kernel, the following vulnerability has been resolved: spi: nxp-fspi: fix the KASAN report out-of-bounds bug Change the memcpy length to fix the out-of-bounds issue when writing the data that is not 4 byte aligned to TX FIFO. To reproduce the issue, write 3 bytes data to NOR chip. dd if=3b of=/dev/mtd0 [ 36.926103] ================================================================== [ 36.933409] BUG: KASAN: slab-out-of-bounds in nxp_fspi_exec_op+0x26ec/0x2838 [ 36.940514] Read of size 4 at addr ffff00081037c2a0 by task dd/455 [ 36.946721] [ 36.948235] CPU: 3 UID: 0 PID: 455 Comm: dd Not tainted 6.11.0-rc5-gc7b0e37c8434 #1070 [ 36.956185] Hardware name: Freescale i.MX8QM MEK (DT) [ 36.961260] Call trace: [ 36.963723] dump_backtrace+0x90/0xe8 [ 36.967414] show_stack+0x18/0x24 [ 36.970749] dump_stack_lvl+0x78/0x90 [ 36.974451] print_report+0x114/0x5cc [ 36.978151] kasan_report+0xa4/0xf0 [ 36.981670] __asan_report_load_n_noabort+0x1c/0x28 [ 36.986587] nxp_fspi_exec_op+0x26ec/0x2838 [ 36.990800] spi_mem_exec_op+0x8ec/0xd30 [ 36.994762] spi_mem_no_dirmap_read+0x190/0x1e0 [ 36.999323] spi_mem_dirmap_write+0x238/0x32c [ 37.003710] spi_nor_write_data+0x220/0x374 [ 37.007932] spi_nor_write+0x110/0x2e8 [ 37.011711] mtd_write_oob_std+0x154/0x1f0 [ 37.015838] mtd_write_oob+0x104/0x1d0 [ 37.019617] mtd_write+0xb8/0x12c [ 37.022953] mtdchar_write+0x224/0x47c [ 37.026732] vfs_write+0x1e4/0x8c8 [ 37.030163] ksys_write+0xec/0x1d0 [ 37.033586] __arm64_sys_write+0x6c/0x9c [ 37.037539] invoke_syscall+0x6c/0x258 [ 37.041327] el0_svc_common.constprop.0+0x160/0x22c [ 37.046244] do_el0_svc+0x44/0x5c [ 37.049589] el0_svc+0x38/0x78 [ 37.052681] el0t_64_sync_handler+0x13c/0x158 [ 37.057077] el0t_64_sync+0x190/0x194 [ 37.060775] [ 37.062274] Allocated by task 455: [ 37.065701] kasan_save_stack+0x2c/0x54 [ 37.069570] kasan_save_track+0x20/0x3c [ 37.073438] kasan_save_alloc_info+0x40/0x54 [ 37.077736] __kasan_kmalloc+0xa0/0xb8 [ 37.081515] __kmalloc_noprof+0x158/0x2f8 [ 37.085563] mtd_kmalloc_up_to+0x120/0x154 [ 37.089690] mtdchar_write+0x130/0x47c [ 37.093469] vfs_write+0x1e4/0x8c8 [ 37.096901] ksys_write+0xec/0x1d0 [ 37.100332] __arm64_sys_write+0x6c/0x9c [ 37.104287] invoke_syscall+0x6c/0x258 [ 37.108064] el0_svc_common.constprop.0+0x160/0x22c [ 37.112972] do_el0_svc+0x44/0x5c [ 37.116319] el0_svc+0x38/0x78 [ 37.119401] el0t_64_sync_handler+0x13c/0x158 [ 37.123788] el0t_64_sync+0x190/0x194 [ 37.127474] [ 37.128977] The buggy address belongs to the object at ffff00081037c2a0 [ 37.128977] which belongs to the cache kmalloc-8 of size 8 [ 37.141177] The buggy address is located 0 bytes inside of [ 37.141177] allocated 3-byte region [ffff00081037c2a0, ffff00081037c2a3) [ 37.153465] [ 37.154971] The buggy address belongs to the physical page: [ 37.160559] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x89037c [ 37.168596] flags: 0xbfffe0000000000(node=0|zone=2|lastcpupid=0x1ffff) [ 37.175149] page_type: 0xfdffffff(slab) [ 37.179021] raw: 0bfffe0000000000 ffff000800002500 dead000000000122 0000000000000000 [ 37.186788] raw: 0000000000000000 0000000080800080 00000001fdffffff 0000000000000000 [ 37.194553] page dumped because: kasan: bad access detected [ 37.200144] [ 37.201647] Memory state around the buggy address: [ 37.206460] ffff00081037c180: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc [ 37.213701] ffff00081037c200: fa fc fc fc 05 fc fc fc 03 fc fc fc 02 fc fc fc [ 37.220946] >ffff00081037c280: 06 fc fc fc 03 fc fc fc fc fc fc fc fc fc fc fc [ 37.228186] ^ [ 37.232473] ffff00081037c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 37.239718] ffff00081037c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 37.246962] ============================================================== ---truncated---
CVSS 3.1 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
The following code attempts to save four different identification numbers into an array.
id_sequence[3] = 456;In the following example, it is possible to request that memcpy move a much larger segment of memory than assumed:
}
.../* if chunk info is valid, return the size of usable memory,* else, return -1 to indicate an error*/...If returnChunkSize() happens to encounter an error it will return -1. Notice that the return value is not checked before the memcpy operation (CWE-252), so -1 can be passed as the size argument to memcpy() (CWE-805). Because memcpy() assumes that the value is unsigned, it will be interpreted as MAXINT-1 (CWE-195), and therefore will copy far more memory than is likely available to the destination buffer (CWE-787, CWE-788).
This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.
}
strcpy(hostname, hp->h_name);/*routine that ensures user_supplied_addr is in the right format for conversion */This function allocates a buffer of 64 bytes to store the hostname, however there is no guarantee that the hostname will not be larger than 64 bytes. If an attacker specifies an address which resolves to a very large hostname, then we may overwrite sensitive data or even relinquish control flow to the attacker.
Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).
This example applies an encoding procedure to an input string and stores it into a buffer.
}
return dst_buf;die("user string too long, die evil hacker!");
else dst_buf[dst_index++] = user_supplied_string[i];dst_buf[dst_index++] = ';';
/* encode to < */The programmer attempts to encode the ampersand character in the user-controlled string, however the length of the string is validated before the encoding procedure is applied. Furthermore, the programmer assumes encoding expansion will only expand a given character by a factor of 4, while the encoding of the ampersand expands by 5. As a result, when the encoding procedure expands the string it is possible to overflow the destination buffer if the attacker provides a string of many ampersands.
In the following C/C++ example, a utility function is used to trim trailing whitespace from a character string. The function copies the input string to a local character string and uses a while statement to remove the trailing whitespace by moving backward through the string and overwriting whitespace with a NUL character.
}
return retMessage;// copy input string to a temporary stringmessage[index] = strMessage[index];// trim trailing whitespacelen--;// return string without trailing whitespaceHowever, this function can cause a buffer underwrite if the input character string contains all whitespace. On some systems the while statement will move backwards past the beginning of a character string and will call the isspace() function on an address outside of the bounds of the local buffer.
The following is an example of code that may result in a buffer underwrite, if find() returns a negative value to indicate that ch is not found in srcBuf:
}...If the index to srcBuf is somehow under user control, this is an arbitrary write-what-where condition.
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