kernel/linux.git/lib/bootconfig.c, branch v5.10.257

lib/bootconfig: check bounds before writing in __xbc_open_brace()

2026-04-18T08:30:57+00:00

commit 560f763baa0f2c9a44da4294c06af071405ac46f upstream. The bounds check for brace_index happens after the array write. While the current call pattern prevents an actual out-of-bounds access (the previous call would have returned an error), the write-before-check pattern is fragile and would become a real out-of-bounds write if the error return were ever not propagated. Move the bounds check before the array write so the function is self-contained and safe regardless of caller behavior. Link: https://lore.kernel.org/all/20260312191143.28719-3-objecting@objecting.org/ Fixes: ead1e19ad905 ("lib/bootconfig: Fix a bug of breaking existing tree nodes") Cc: stable@vger.kernel.org Signed-off-by: Josh Law Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

lib/bootconfig: fix snprintf truncation check in xbc_node_compose_key_after()

2026-04-18T08:30:57+00:00

commit 1120a36bb1e9b9e22de75ecb4ef0b998f73a97f1 upstream. snprintf() returns the number of characters that would have been written excluding the NUL terminator. Output is truncated when the return value is >= the buffer size, not just > the buffer size. When ret == size, the current code takes the non-truncated path, advancing buf by ret and reducing size to 0. This is wrong because the output was actually truncated (the last character was replaced by NUL). Fix by using >= so the truncation path is taken correctly. Link: https://lore.kernel.org/all/20260312191143.28719-4-objecting@objecting.org/ Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: stable@vger.kernel.org Signed-off-by: Josh Law Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

lib/bootconfig: fix off-by-one in xbc_verify_tree() unclosed brace error

2026-04-18T08:30:56+00:00

commit 39ebc8d7f561e1b64eca87353ef9b18e2825e591 upstream. __xbc_open_brace() pushes entries with post-increment (open_brace[brace_index++]), so brace_index always points one past the last valid entry. xbc_verify_tree() reads open_brace[brace_index] to report which brace is unclosed, but this is one past the last pushed entry and contains stale/zero data, causing the error message to reference the wrong node. Use open_brace[brace_index - 1] to correctly identify the unclosed brace. brace_index is known to be > 0 here since we are inside the if (brace_index) guard. Link: https://lore.kernel.org/all/20260312191143.28719-2-objecting@objecting.org/ Fixes: ead1e19ad905 ("lib/bootconfig: Fix a bug of breaking existing tree nodes") Cc: stable@vger.kernel.org Signed-off-by: Josh Law Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

lib/bootconfig: Fix to remove tailing spaces after value

2020-09-22T01:50:09+00:00

Fix to remove tailing spaces after value. If there is a space after value, the bootconfig failed to remove it because it applies strim() before replacing the delimiter with null. For example, foo = var # comment was parsed as below. foo="var " but user will expect foo="var" This fixes it by applying strim() after removing the delimiter. Link: https://lkml.kernel.org/r/160068149134.1088739.8868306567670058853.stgit@devnote2 Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

lib/bootconfig: Fix a bug of breaking existing tree nodes

2020-09-22T01:45:52+00:00

Fix a bug of breaking existing tree nodes by parsing the second and subsequent braces. Since the bootconfig parser uses the node.next field as a flag of current parent node, but this will break the existing tree if the same key node is specified again in the bootconfig. For example, the following bootconfig should be foo.buz and bar. foo bar foo { buz } However, when parsing the brace "{", it breaks foo->bar link by marking open-brace node. So the bootconfig unlinks bar from the bootconfig internal tree. This introduces a stack outside of the tree and record the last open-brace on the stack instead of using node.next field. Link: https://lkml.kernel.org/r/160068148267.1088739.8264704338030168660.stgit@devnote2 Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

lib: Revert use of fallthrough pseudo-keyword in lib/

2020-08-24T21:17:44+00:00

The following build error for powerpc64 was reported by Nathan Chancellor: "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage ... In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234, from arch/powerpc/boot/decompress.c:38: arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main': arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function) 586 | fallthrough; | ^~~~~~~~~~~ This will end up affecting distribution configurations such as Debian and OpenSUSE according to my testing. I am not sure what the solution is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure that compiler_attributes.h can be safely included." In order to avoid these sort of problems, it seems that the best solution is to use /* fall through */ comments instead of the fallthrough pseudo-keyword macro in lib/, for now. Reported-by: Nathan Chancellor Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword") Signed-off-by: Gustavo A. R. Silva Reviewed-and-tested-by: Nathan Chancellor Signed-off-by: Linus Torvalds

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

lib/bootconfig: Add override operator support

2020-08-03T20:22:28+00:00

Add the value override operator (":=") support to the bootconfig. This value override operator will be useful for the bootloaders which will only update the existing bootconfig according to the bootloader boot options. Without this override operator, the bootloader needs to parse the existing bootconfig and update it. However, with this assignment, it can just append the updated (partial) bootconfig text at the tail of existing one without parsing it. (Of course, it must update the size, checksum and magic, but that will be done easily) Link: https://lkml.kernel.org/r/159482882954.126704.16209517125614438640.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

tools/bootconfig: Show line and column in parse error

2020-03-03T22:38:42+00:00

Show line and column when we got a parse error in bootconfig tool. Current lib/bootconfig shows the parse error with byte offset, but that is not human readable. This makes xbc_init() not showing error message itself but able to pass the error message and position to caller, so that the caller can decode it and show the error message with line number and columns. With this patch, bootconfig tool shows an error with line:column as below. $ cat samples/bad-dotword.bconf # do not start keyword with . key { .word = 1 } $ ./bootconfig -a samples/bad-dotword.bconf initrd Parse Error: Invalid keyword at 3:3 Link: http://lkml.kernel.org/r/158323469002.10560.4023923847704522760.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

bootconfig: Add append value operator support

2020-02-21T14:59:39+00:00

Add append value operator "+=" support to bootconfig syntax. With this operator, user can add new value to the key as an entry of array instead of overwriting. For example, foo = bar ... foo += baz Then the key "foo" has "bar" and "baz" values as an array. Link: http://lkml.kernel.org/r/158227283195.12842.8310503105963275584.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)