riscv/qemu - qemu - Gitea: Git with a cup of tea

Author	SHA1	Message	Date
Richard Henderson	ee3b39c924	linux-user: Create vdso_sigreturn_region_{start,end} These variables will be populated from the vdso, and used for detecting whether we are executing the sigreturn. Signed-off-by: Richard Henderson <richard.henderson@linaro.org>	8 months ago
Peter Maydell	cb8607b89f	linux-user/gen-vdso: Don't read off the end of buf[] In gen-vdso we load in a file and assume it's a valid ELF file. In particular we assume it's big enough to be able to read the ELF information in e_ident in the ELF header. Add a check that the total file length is at least big enough for all the e_ident bytes, which is good enough for the code in gen-vdso.c. This will catch the most obvious possible bad input file (truncated) and allow us to run the sanity checks like "not actually an ELF file" without potentially crashing. The code in elf32_process() and elf64_process() still makes assumptions about the file being well-formed, but this is OK because we only run it on the vdso binaries that we create ourselves in the build process by running the compiler. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-ID: <20250710170707.1299926-3-peter.maydell@linaro.org>	9 months ago
Peter Maydell	ff3b0e8d32	linux-user/gen-vdso: Handle fseek() failure Coverity points out that we don't check for fseek() failure in gen-vdso.c, and so we might pass -1 to malloc(). Add the error checking. (This is a standalone executable that doesn't link against glib, so we can't do the easy thing and use g_file_get_contents().) Coverity: CID 1523742 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-ID: <20250710170707.1299926-2-peter.maydell@linaro.org>	9 months ago
Daniel P. Berrangé	5171b794d4	linux-user: fix resource leaks in gen-vdso There are a number of resource leaks in gen-vdso. In theory they are harmless because this is a short lived process, but when building QEMU with --extra-cflags="-fsanitize=address" problems ensure. The gen-vdso program is run as part of the build, and that aborts due to the sanitizer identifying memory leaks, leaving QEMU unbuildable. FAILED: libqemu-x86_64-linux-user.a.p/vdso.c.inc /var/home/berrange/src/virt/qemu/build/linux-user/gen-vdso -o libqemu-x86_64-linux-user.a.p/vdso.c.inc ../linux-user/x86_64/vdso.so ================================================================= ==1696332==ERROR: LeakSanitizer: detected memory leaks Direct leak of 2968 byte(s) in 1 object(s) allocated from: #0 0x56495873f1f3 (/var/home/berrange/src/virt/qemu/build/linux-user/gen-vdso+0xa11f3) (BuildId: b69e241ad44719b6f3934f3c71dfc6727e8bdb12) #1 0x564958780b90 (/var/home/berrange/src/virt/qemu/build/linux-user/gen-vdso+0xe2b90) (BuildId: b69e241ad44719b6f3934f3c71dfc6727e8bdb12) This complaint is about the 'buf' variable, however, the FILE objects are also leaked in some error scenarios, so this fix refactors the cleanup paths to fix all leaks. For completeness it also reports an error if fclose() fails on 'inf'. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Tested-by: Arusekk <floss@arusekk.pl> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-ID: <20250513150346.1328217-1-berrange@redhat.com>	11 months ago
Ilya Leoshkevich	6e9dcfb906	linux-user: Fix GDB complaining about system-supplied DSO string table index When debugging qemu-user processes using gdbstub, the following warning appears every time: warning: BFD: warning: system-supplied DSO at 0x7f8253cc3000 has a corrupt string table index The reason is that QEMU does not map the VDSO's section headers. The VDSO's ELF header's e_shoff points to zeros, which GDB fails to parse. The difference with the kernel's VDSO is that the latter is mapped as a blob, ignoring program headers - which also don't cover the section table. QEMU, on the other hand, loads it as an ELF file. There appears to be no way to place section headers inside a section, and, therefore, no way to refer to them from a linker script. Also, ld hardcodes section headers to be non-loadable, see _bfd_elf_assign_file_positions_for_non_load(). In theory ld could be enhanced by implementing an "SHDRS" keyword in addition to the existing "FILEHDR" and "PHDRS". There are multiple ways to resolve the issue: - Copy VDSO as a blob in load_elf_vdso(). This would require creating specialized loader logic, that duplicates parts of load_elf_image(). - Fix up VDSO's PHDR size in load_elf_vdso(). This would require either duplicating the parsing logic, or adding an ugly parameter to load_elf_image(). - Fix up VDSO's PHDR size in gen-vdso. This is the simplest solution, so do it. There are two tricky parts: - Byte-swaps need to be done either on local copies, or in-place and then reverted in the end. To preserve the existing code structure, do the former for Sym and Dyn, and the latter for Ehdr, Phdr, and Shdr. - There must be no .bss, which is already the case - but having an explicit check is helpful to ensure correctness. To verify this change, I diffed the on-disk and the loaded VDSOs; the result does not show anything unusual, except for what seems to be an existing oversight (which should probably be fixed separately): │ Symbol table '.dynsym' contains 8 entries: │ Num: Value Size Type Bind Vis Ndx Name │ - 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND │ - 6: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.29 │ + 0: 00007f61075bf000 0 NOTYPE LOCAL DEFAULT UND │ + 6: 00007f61075bf000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.29 Fixes: `2fa536d107` ("linux-user: Add gen-vdso tool") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-ID: <20241023202850.55211-1-iii@linux.ibm.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>	2 years ago
Richard Henderson	2fa536d107	linux-user: Add gen-vdso tool This tool will be used for post-processing the linked vdso image, turning it into something that is easy to include into elfload.c. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>	5 years ago