179 lines
4.5 KiB
Diff
179 lines
4.5 KiB
Diff
From 10a01bcdd748773c185255516a72e75a71295bd4 Mon Sep 17 00:00:00 2001
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From: "Darrick J. Wong" <djwong@kernel.org>
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Date: Thu, 15 Jun 2023 09:11:04 -0700
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Subject: [PATCH] xfs_db: fix metadump name obfuscation for ascii-ci
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filesystems
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Now that we've stabilized the dirent hash function for ascii-ci
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filesystems, adapt the metadump name obfuscation code to detect when
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it's obfuscating a directory entry name on an ascii-ci filesystem and
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spit out names that actually have the same hash.
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Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Reviewed-by: Eric Sandeen <sandeen@redhat.com>
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Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
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Signed-off-by: Carlos Maiolino <cem@kernel.org>
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Signed-off-by: Pavel Reichl <preichl@redhat.com>
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---
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db/metadump.c | 82 +++++++++++++++++++++++++++++++++++++++++++++------
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1 file changed, 73 insertions(+), 9 deletions(-)
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diff --git a/db/metadump.c b/db/metadump.c
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index 317ff728..9ccee0b7 100644
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--- a/db/metadump.c
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+++ b/db/metadump.c
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@@ -817,13 +817,17 @@ static void
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obfuscate_name(
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xfs_dahash_t hash,
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size_t name_len,
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- unsigned char *name)
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+ unsigned char *name,
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+ bool is_dirent)
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{
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- unsigned char *newp = name;
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+ unsigned char *oldname = NULL;
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+ unsigned char *newp;
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int i;
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- xfs_dahash_t new_hash = 0;
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+ xfs_dahash_t new_hash;
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unsigned char *first;
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unsigned char high_bit;
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+ int tries = 0;
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+ bool is_ci_name = is_dirent && xfs_has_asciici(mp);
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int shift;
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/*
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@@ -836,6 +840,26 @@ obfuscate_name(
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if (name_len < 5)
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return;
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+ if (is_ci_name) {
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+ oldname = malloc(name_len);
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+ if (!oldname)
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+ return;
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+ memcpy(oldname, name, name_len);
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+ }
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+
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+again:
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+ newp = name;
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+ new_hash = 0;
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+
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+ /*
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+ * If we cannot generate a ci-compatible obfuscated name after 1000
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+ * tries, don't bother obfuscating the name.
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+ */
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+ if (tries++ > 1000) {
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+ memcpy(name, oldname, name_len);
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+ goto out_free;
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+ }
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+
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/*
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* The beginning of the obfuscated name can be pretty much
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* anything, so fill it in with random characters.
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@@ -843,7 +867,11 @@ obfuscate_name(
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*/
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for (i = 0; i < name_len - 5; i++) {
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*newp = random_filename_char();
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- new_hash = *newp ^ rol32(new_hash, 7);
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+ if (is_ci_name)
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+ new_hash = xfs_ascii_ci_xfrm(*newp) ^
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+ rol32(new_hash, 7);
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+ else
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+ new_hash = *newp ^ rol32(new_hash, 7);
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newp++;
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}
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@@ -867,6 +895,17 @@ obfuscate_name(
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high_bit = 0x80;
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} else
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high_bit = 0;
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+
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+ /*
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+ * If ascii-ci is enabled, uppercase characters are converted
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+ * to lowercase characters while computing the name hash. If
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+ * any of the necessary correction bytes are uppercase, the
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+ * hash of the new name will not match. Try again with a
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+ * different prefix.
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+ */
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+ if (is_ci_name && xfs_ascii_ci_need_xfrm(*newp))
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+ goto again;
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+
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ASSERT(!is_invalid_char(*newp));
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newp++;
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}
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@@ -880,8 +919,15 @@ obfuscate_name(
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*/
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if (high_bit) {
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*first ^= 0x10;
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+
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+ if (is_ci_name && xfs_ascii_ci_need_xfrm(*first))
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+ goto again;
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+
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ASSERT(!is_invalid_char(*first));
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}
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+
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+out_free:
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+ free(oldname);
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}
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/*
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@@ -1177,6 +1223,24 @@ handle_duplicate_name(xfs_dahash_t hash, size_t name_len, unsigned char *name)
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return 1;
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}
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+static inline xfs_dahash_t
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+dirattr_hashname(
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+ bool is_dirent,
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+ const uint8_t *name,
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+ int namelen)
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+{
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+ if (is_dirent) {
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+ struct xfs_name xname = {
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+ .name = name,
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+ .len = namelen,
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+ };
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+
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+ return libxfs_dir2_hashname(mp, &xname);
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+ }
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+
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+ return libxfs_da_hashname(name, namelen);
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+}
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+
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static void
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generate_obfuscated_name(
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xfs_ino_t ino,
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@@ -1205,9 +1269,9 @@ generate_obfuscated_name(
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/* Obfuscate the name (if possible) */
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- hash = libxfs_da_hashname(name, namelen);
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- obfuscate_name(hash, namelen, name);
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- ASSERT(hash == libxfs_da_hashname(name, namelen));
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+ hash = dirattr_hashname(ino != 0, name, namelen);
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+ obfuscate_name(hash, namelen, name, ino != 0);
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+ ASSERT(hash == dirattr_hashname(ino != 0, name, namelen));
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/*
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* Make sure the name is not something already seen. If we
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@@ -1320,7 +1384,7 @@ obfuscate_path_components(
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/* last (or single) component */
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namelen = strnlen((char *)comp, len);
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hash = libxfs_da_hashname(comp, namelen);
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- obfuscate_name(hash, namelen, comp);
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+ obfuscate_name(hash, namelen, comp, false);
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ASSERT(hash == libxfs_da_hashname(comp, namelen));
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break;
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}
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@@ -1332,7 +1396,7 @@ obfuscate_path_components(
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continue;
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}
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hash = libxfs_da_hashname(comp, namelen);
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- obfuscate_name(hash, namelen, comp);
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+ obfuscate_name(hash, namelen, comp, false);
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ASSERT(hash == libxfs_da_hashname(comp, namelen));
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comp += namelen + 1;
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len -= namelen + 1;
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--
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2.41.0
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