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Revert "parser: fix potential padding bug."

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This reverts commit 78ae95608753b42956f2445a4965b0577fbb76de.

Commit 78ae95608753b42956f2445a4965b0577fbb76de causes policy to not
to conform to protocol as determined by the kernel. Technically the
reverted patch is correct and the kernel is wrong but we can not
change 15 years of history.

The reason it breaks the policy in the kernel is because the kernel
does not use the name field, and does not expect it. It just expects
the size with a single trailing 0. This doesn't break because this
section is all padded to 64 bytes so writing the extra 0 doesn't
hurt as it is effectively just manually adding to the padding.

Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2024-07-18 06:15:05 -07:00
parent 0d9d548694
commit 42523bae91
1 changed files with 2 additions and 2 deletions
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4
parser/libapparmor_re/chfa.cc
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@ -419,7 +419,7 @@ void CHFA::flex_table(ostream &os, const char *name)
/* Write the actual flex parser table. */
/* TODO: add max_oob */
size_t hsize = pad64(sizeof(th) + sizeof(th_version) + 1 + strlen(name) + 1);
size_t hsize = pad64(sizeof(th) + sizeof(th_version) + strlen(name) + 1);
th.th_magic = htonl(YYTH_REGEX_MAGIC);
th.th_flags = htons(chfaflags);
th.th_hsize = htonl(hsize);
@ -433,7 +433,7 @@ void CHFA::flex_table(ostream &os, const char *name)
flex_table_size(check_vec.begin(), check_vec.end()));
os.write((char *)&th, sizeof(th));
os << th_version << (char)0 << name << (char)0;
os << fill64(sizeof(th) + 1 + sizeof(th_version) + strlen(name) + 1);
os << fill64(sizeof(th) + sizeof(th_version) + strlen(name) + 1);
write_flex_table(os, YYTD_ID_ACCEPT, accept.begin(), accept.end());
write_flex_table(os, YYTD_ID_ACCEPT2, accept2.begin(), accept2.end());