From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/nls/nls_utf8.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 fs/nls/nls_utf8.c (limited to 'fs/nls/nls_utf8.c') diff --git a/fs/nls/nls_utf8.c b/fs/nls/nls_utf8.c new file mode 100644 index 000000000..a0fa0610e --- /dev/null +++ b/fs/nls/nls_utf8.c @@ -0,0 +1,68 @@ +/* + * Module for handling utf8 just like any other charset. + * By Urban Widmark 2000 + */ + +#include +#include +#include +#include +#include + +static unsigned char identity[256]; + +static int uni2char(wchar_t uni, unsigned char *out, int boundlen) +{ + int n; + + if (boundlen <= 0) + return -ENAMETOOLONG; + + n = utf32_to_utf8(uni, out, boundlen); + if (n < 0) { + *out = '?'; + return -EINVAL; + } + return n; +} + +static int char2uni(const unsigned char *rawstring, int boundlen, wchar_t *uni) +{ + int n; + unicode_t u; + + n = utf8_to_utf32(rawstring, boundlen, &u); + if (n < 0 || u > MAX_WCHAR_T) { + *uni = 0x003f; /* ? */ + return -EINVAL; + } + *uni = (wchar_t) u; + return n; +} + +static struct nls_table table = { + .charset = "utf8", + .uni2char = uni2char, + .char2uni = char2uni, + .charset2lower = identity, /* no conversion */ + .charset2upper = identity, +}; + +static int __init init_nls_utf8(void) +{ + int i; + for (i=0; i<256; i++) + identity[i] = i; + + return register_nls(&table); +} + +static void __exit exit_nls_utf8(void) +{ + unregister_nls(&table); +} + +module_init(init_nls_utf8) +module_exit(exit_nls_utf8) +MODULE_DESCRIPTION("NLS UTF-8"); +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.3.1