On 1/29/20 9:44 AM, Markus Klotzbuecher wrote:
Hi Heinrich
On Sat, Jan 25, 2020 at 10:46:04PM +0100, Heinrich Schuchardt wrote:
On 5/15/19 3:15 PM, Markus Klotzbuecher wrote:
From: Markus Klotzbuecher markus.klotzbuecher@kistler.com
Add support for expanding simple expressions and sizes such as "(4 * 1024)", "(512 << 10)" or "(SZ_256K)".
This can help to significantly reduce the number of "suspicious" moves, such as
'CONFIG_ENV_SIZE="(64 << 10)"' was removed by savedefconfig.
If the expansion fails, it falls back to the original string.
Signed-off-by: Markus Klotzbuecher markus.klotzbuecher@kistler.com Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Heiko Schocher hs@denx.de
Changes for v2: new patch
tools/moveconfig.py | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)
diff --git a/tools/moveconfig.py b/tools/moveconfig.py index 1a214c5605..0bbc7c1991 100755 --- a/tools/moveconfig.py +++ b/tools/moveconfig.py @@ -354,6 +354,26 @@ CONFIG_DATABASE = 'moveconfig.db'
CONFIG_LEN = len('CONFIG_')
+SIZES = {
- "SZ_1": 0x00000001, "SZ_2": 0x00000002,
- "SZ_4": 0x00000004, "SZ_8": 0x00000008,
- "SZ_16": 0x00000010, "SZ_32": 0x00000020,
- "SZ_64": 0x00000040, "SZ_128": 0x00000080,
- "SZ_256": 0x00000100, "SZ_512": 0x00000200,
- "SZ_1K": 0x00000400, "SZ_2K": 0x00000800,
- "SZ_4K": 0x00001000, "SZ_8K": 0x00002000,
- "SZ_16K": 0x00004000, "SZ_32K": 0x00008000,
- "SZ_64K": 0x00010000, "SZ_128K": 0x00020000,
- "SZ_256K": 0x00040000, "SZ_512K": 0x00080000,
- "SZ_1M": 0x00100000, "SZ_2M": 0x00200000,
- "SZ_4M": 0x00400000, "SZ_8M": 0x00800000,
- "SZ_16M": 0x01000000, "SZ_32M": 0x02000000,
- "SZ_64M": 0x04000000, "SZ_128M": 0x08000000,
- "SZ_256M": 0x10000000, "SZ_512M": 0x20000000,
- "SZ_1G": 0x40000000, "SZ_2G": 0x80000000,
- "SZ_4G": 0x100000000
+}
- ### helper functions ### def get_devnull(): """Get the file object of '/dev/null' device."""
@@ -777,6 +797,25 @@ def cleanup_readme(configs, options): with open('README', 'w') as f: f.write(''.join(newlines))
+def try_expand(line):
- """If value looks like an expression, try expanding it
- Otherwise just return the existing value
- """
- if line.find('=') == -1:
return line- try:
cfg, val = re.split("=", line)val= val.strip('\"')if re.search("[*+-/]|<<|SZ_+|\(([^\)]+)\)", val):newval = hex(eval(val, SIZES))The if clause evaluates to true for values like:
val = "os.execl('/sbin/fdisk')"As eval() can be used to execute arbitrary commands this patch should be corrected.
Fair point. I took a quick look at python sandboxing, and apparently it's difficult to be done in a secure way (see pysandbox). As introducing a CONFIG with something like the above clearly has malicious intent, just preventing "accidential" execution will not be sufficient. Perhaps we can use ast.literal_eval instead. I'll take a closer look.
Except for the strings starting with SZ_ that you defined we would not expect any letters in the term to evaluate. This could be checked using a suitable regular expression.
Best regards
Heinrich