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BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_COUNT_TWO(0.00)[2]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCPT_COUNT_FIVE(0.00)[5]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Level: Covered in Documentation/driver-api/early-userspace/buffer-format.rst , initramfs archives can carry an optional "TRAILER!!!" entry which serves as a boundary for collecting and associating hardlinks with matching inode and major / minor device numbers. Although optional, if hardlinks are found in an archive without a subsequent "TRAILER!!!" entry then the hardlink state hash table is leaked, e.g. unfixed kernel, with initramfs_test.c hunk applied only: unreferenced object 0xffff9405408cc000 (size 8192): comm "kunit_try_catch", pid 53, jiffies 4294892519 hex dump (first 32 bytes): 01 00 00 00 01 00 00 00 00 00 00 00 ff 81 00 00 ................ 00 00 00 00 00 00 00 00 69 6e 69 74 72 61 6d 66 ........initramf backtrace (crc a9fb0ee0): [<0000000066739faa>] __kmalloc_cache_noprof+0x11d/0x250 [<00000000fc755219>] maybe_link.part.5+0xbc/0x120 [<000000000526a128>] do_name+0xce/0x2f0 [<00000000145c1048>] write_buffer+0x22/0x40 [<000000003f0b4f32>] unpack_to_rootfs+0xf9/0x2a0 [<00000000d6f7e5af>] initramfs_test_hardlink+0xe3/0x3f0 [<0000000014fde8d6>] kunit_try_run_case+0x5f/0x130 [<00000000dc9dafc5>] kunit_generic_run_threadfn_adapter+0x18/0x30 [<000000001076c239>] kthread+0xc8/0x100 [<00000000d939f1c1>] ret_from_fork+0x2b/0x40 [<00000000f848ad1a>] ret_from_fork_asm+0x1a/0x30 Fix this by calling free_hash() after initramfs buffer processing in unpack_to_rootfs(). An extra hardlink_seen global is added as an optimization to avoid walking the 32 entry hash array unnecessarily. The expectation is that a "TRAILER!!!" entry will normally be present, and initramfs hardlinks are uncommon. There is one user facing side-effect of this fix: hardlinks can currently be associated across built-in and external initramfs archives, *if* the built-in initramfs archive lacks a "TRAILER!!!" terminator. I'd consider this cross-archive association broken, but perhaps it's used. Signed-off-by: David Disseldorp --- init/initramfs.c | 7 ++++++- init/initramfs_test.c | 5 ----- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/init/initramfs.c b/init/initramfs.c index c264f136c5281..99f3cac10d392 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -76,6 +76,7 @@ static __initdata struct hash { struct hash *next; char name[N_ALIGN(PATH_MAX)]; } *head[32]; +static __initdata bool hardlink_seen; static inline int hash(int major, int minor, int ino) { @@ -109,19 +110,21 @@ static char __init *find_link(int major, int minor, int ino, strcpy(q->name, name); q->next = NULL; *p = q; + hardlink_seen = true; return NULL; } static void __init free_hash(void) { struct hash **p, *q; - for (p = head; p < head + 32; p++) { + for (p = head; hardlink_seen && p < head + 32; p++) { while (*p) { q = *p; *p = q->next; kfree(q); } } + hardlink_seen = false; } #ifdef CONFIG_INITRAMFS_PRESERVE_MTIME @@ -563,6 +566,8 @@ char * __init unpack_to_rootfs(char *buf, unsigned long len) len -= my_inptr; } dir_utime(); + /* free any hardlink state collected without optional TRAILER!!! */ + free_hash(); kfree(cpio_buf); return message; } diff --git a/init/initramfs_test.c b/init/initramfs_test.c index 84b21f465bc3d..a2930c70cc817 100644 --- a/init/initramfs_test.c +++ b/init/initramfs_test.c @@ -319,11 +319,6 @@ static void __init initramfs_test_hardlink(struct kunit *test) .namesize = sizeof("initramfs_test_hardlink_link"), .fname = "initramfs_test_hardlink_link", .data = "ASDF", - }, { - /* hardlink hashtable leaks when the archive omits a trailer */ - .magic = "070701", - .namesize = sizeof("TRAILER!!!"), - .fname = "TRAILER!!!", } }; cpio_srcbuf = kmalloc(8192, GFP_KERNEL);