summaryrefslogtreecommitdiffstats
path: root/kernel/kallsyms.c
diff options
context:
space:
mode:
authorMiguel Ojeda <ojeda@kernel.org>2021-04-05 04:58:39 +0200
committerMiguel Ojeda <ojeda@kernel.org>2022-09-28 08:56:08 +0200
commit73bbb94466fd3f8b313eeb0b0467314a262dddb3 (patch)
tree59db1039bae509a80bc1753ce21bbbc8b3e6c7ad /kernel/kallsyms.c
parent6e8c5bbd5e83e649251c198e743c8b9e7c48372b (diff)
downloadlinux-stable-73bbb94466fd3f8b313eeb0b0467314a262dddb3.tar.gz
linux-stable-73bbb94466fd3f8b313eeb0b0467314a262dddb3.tar.bz2
linux-stable-73bbb94466fd3f8b313eeb0b0467314a262dddb3.zip
kallsyms: support "big" kernel symbols
Rust symbols can become quite long due to namespacing introduced by modules, types, traits, generics, etc. Increasing to 255 is not enough in some cases, therefore introduce longer lengths to the symbol table. In order to avoid increasing all lengths to 2 bytes (since most of them are small, including many Rust ones), use ULEB128 to keep smaller symbols in 1 byte, with the rest in 2 bytes. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'kernel/kallsyms.c')
-rw-r--r--kernel/kallsyms.c26
1 files changed, 22 insertions, 4 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 3e7e2c2ad2f7..fc5e26348d25 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -50,12 +50,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off,
data = &kallsyms_names[off];
len = *data;
data++;
+ off++;
+
+ /* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
+ if ((len & 0x80) != 0) {
+ len = (len & 0x7F) | (*data << 7);
+ data++;
+ off++;
+ }
/*
* Update the offset to return the offset for the next symbol on
* the compressed stream.
*/
- off += len + 1;
+ off += len;
/*
* For every byte on the compressed symbol data, copy the table
@@ -108,7 +116,7 @@ static char kallsyms_get_symbol_type(unsigned int off)
static unsigned int get_symbol_offset(unsigned long pos)
{
const u8 *name;
- int i;
+ int i, len;
/*
* Use the closest marker we have. We have markers every 256 positions,
@@ -122,8 +130,18 @@ static unsigned int get_symbol_offset(unsigned long pos)
* so we just need to add the len to the current pointer for every
* symbol we wish to skip.
*/
- for (i = 0; i < (pos & 0xFF); i++)
- name = name + (*name) + 1;
+ for (i = 0; i < (pos & 0xFF); i++) {
+ len = *name;
+
+ /*
+ * If MSB is 1, it is a "big" symbol, so we need to look into
+ * the next byte (and skip it, too).
+ */
+ if ((len & 0x80) != 0)
+ len = ((len & 0x7F) | (name[1] << 7)) + 1;
+
+ name = name + len + 1;
+ }
return name - kallsyms_names;
}