user/sven/linux.git/kernel/kexec_file.c, branch v4.18-rc2

treewide: Use array_size() in vzalloc()

2018-06-12T23:19:22Z

The vzalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vzalloc(a * b) with: vzalloc(array_size(a, b)) as well as handling cases of: vzalloc(a * b * c) with: vzalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vzalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(char) * COUNT + COUNT , ...) | vzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vzalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vzalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vzalloc(C1 * C2 * C3, ...) | vzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vzalloc(C1 * C2, ...) | vzalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook

kernel/kexec_file.c: allow archs to set purgatory load address

2018-04-14T00:10:28Z

For s390 new kernels are loaded to fixed addresses in memory before they are booted. With the current code this is a problem as it assumes the kernel will be loaded to an 'arbitrary' address. In particular, kexec_locate_mem_hole searches for a large enough memory region and sets the load address (kexec_bufer->mem) to it. Luckily there is a simple workaround for this problem. By returning 1 in arch_kexec_walk_mem, kexec_locate_mem_hole is turned off. This allows the architecture to set kbuf->mem by hand. While the trick works fine for the kernel it does not for the purgatory as here the architectures don't have access to its kexec_buffer. Give architectures access to the purgatories kexec_buffer by changing kexec_load_purgatory to take a pointer to it. With this change architectures have access to the buffer and can edit it as they need. A nice side effect of this change is that we can get rid of the purgatory_info->purgatory_load_address field. As now the information stored there can directly be accessed from kbuf->mem. Link: http://lkml.kernel.org/r/20180321112751.22196-11-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Reviewed-by: Martin Schwidefsky Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: remove mis-use of sh_offset field during purgatory load

2018-04-14T00:10:28Z

The current code uses the sh_offset field in purgatory_info->sechdrs to store a pointer to the current load address of the section. Depending whether the section will be loaded or not this is either a pointer into purgatory_info->purgatory_buf or kexec_purgatory. This is not only a violation of the ELF standard but also makes the code very hard to understand as you cannot tell if the memory you are using is read-only or not. Remove this misuse and store the offset of the section in pugaroty_info->purgatory_buf in sh_offset. Link: http://lkml.kernel.org/r/20180321112751.22196-10-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: remove unneeded variables in kexec_purgatory_setup_sechdrs

2018-04-14T00:10:28Z

The main loop currently uses quite a lot of variables to update the section headers. Some of them are unnecessary. So clean them up a little. Link: http://lkml.kernel.org/r/20180321112751.22196-9-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: remove unneeded for-loop in kexec_purgatory_setup_sechdrs

2018-04-14T00:10:28Z

To update the entry point there is an extra loop over all section headers although this can be done in the main loop. So move it there and eliminate the extra loop and variable to store the 'entry section index'. Also, in the main loop, move the usual case, i.e. non-bss section, out of the extra if-block. Link: http://lkml.kernel.org/r/20180321112751.22196-8-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Reviewed-by: Martin Schwidefsky Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: split up __kexec_load_puragory

2018-04-14T00:10:28Z

When inspecting __kexec_load_purgatory you find that it has two tasks 1) setting up the kexec_buffer for the new kernel and, 2) setting up pi->sechdrs for the final load address. The two tasks are independent of each other. To improve readability split up __kexec_load_purgatory into two functions, one for each task, and call them directly from kexec_load_purgatory. Link: http://lkml.kernel.org/r/20180321112751.22196-7-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: use read-only sections in arch_kexec_apply_relocations*

2018-04-14T00:10:28Z

When the relocations are applied to the purgatory only the section the relocations are applied to is writable. The other sections, i.e. the symtab and .rel/.rela, are in read-only kexec_purgatory. Highlight this by marking the corresponding variables as 'const'. While at it also change the signatures of arch_kexec_apply_relocations* to take section pointers instead of just the index of the relocation section. This removes the second lookup and sanity check of the sections in arch code. Link: http://lkml.kernel.org/r/20180321112751.22196-6-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: search symbols in read-only kexec_purgatory

2018-04-14T00:10:28Z

The stripped purgatory does not contain a symtab. So when looking for symbols this is done in read-only kexec_purgatory. Highlight this by marking the corresponding variables as 'const'. Link: http://lkml.kernel.org/r/20180321112751.22196-5-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: make purgatory_info->ehdr const

2018-04-14T00:10:28Z

The kexec_purgatory buffer is read-only. Thus all pointers into kexec_purgatory are read-only, too. Point this out by explicitly marking purgatory_info->ehdr as 'const' and update the comments in purgatory_info. Link: http://lkml.kernel.org/r/20180321112751.22196-4-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/kexec_file.c: remove checks in kexec_purgatory_load

2018-04-14T00:10:28Z

Before the purgatory is loaded several checks are done whether the ELF file in kexec_purgatory is valid or not. These checks are incomplete. For example they don't check for the total size of the sections defined in the section header table or if the entry point actually points into the purgatory. On the other hand the purgatory, although an ELF file on its own, is part of the kernel. Thus not trusting the purgatory means not trusting the kernel build itself. So remove all validity checks on the purgatory and just trust the kernel build. Link: http://lkml.kernel.org/r/20180321112751.22196-3-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds