From 836b2fe544a5e9b5ce116622cb36fba33838c6fd Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 01:33:23 -0700 Subject: selftests/bpf: Check that JMP32 pointer vs zero jumps are not predicted Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which the verifier used to skip, contains an out of bounds map value access, hence w/o the previous patch the program is accepted. See previous patch for detailed description. Reported-by: Nicholas Carlini Suggested-by: Nicholas Carlini Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- fs/proc/thread_self.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 fs/proc/thread_self.c (limited to 'fs/proc/thread_self.c') diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c new file mode 100644 index 000000000..61ac62c3f --- /dev/null +++ b/fs/proc/thread_self.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include "internal.h" + +/* + * /proc/thread_self: + */ +static const char *proc_thread_self_get_link(struct dentry *dentry, + struct inode *inode, + struct delayed_call *done) +{ + struct pid_namespace *ns = proc_pid_ns(inode->i_sb); + pid_t tgid = task_tgid_nr_ns(current, ns); + pid_t pid = task_pid_nr_ns(current, ns); + char *name; + + if (!pid) + return ERR_PTR(-ENOENT); + name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC); + if (unlikely(!name)) + return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); + sprintf(name, "%u/task/%u", tgid, pid); + set_delayed_call(done, kfree_link, name); + return name; +} + +static const struct inode_operations proc_thread_self_inode_operations = { + .get_link = proc_thread_self_get_link, +}; + +unsigned thread_self_inum __ro_after_init; + +int proc_setup_thread_self(struct super_block *s) +{ + struct dentry *thread_self; + int ret = -ENOMEM; + + thread_self = d_alloc_name(s->s_root, "thread-self"); + if (thread_self) { + struct inode *inode = new_inode(s); + if (inode) { + inode->i_ino = thread_self_inum; + simple_inode_init_ts(inode); + inode->i_mode = S_IFLNK | S_IRWXUGO; + inode->i_uid = GLOBAL_ROOT_UID; + inode->i_gid = GLOBAL_ROOT_GID; + inode->i_op = &proc_thread_self_inode_operations; + d_make_persistent(thread_self, inode); + ret = 0; + } + dput(thread_self); + } + + if (ret) + pr_err("proc_fill_super: can't allocate /proc/thread-self\n"); + return ret; +} + +void __init proc_thread_self_init(void) +{ + proc_alloc_inum(&thread_self_inum); +} -- cgit v1.3.1